Classy is the world’s largest fundraising platform for social good organizations

BUILD LIFELONG RELATIONSHIPS FROM MOMENTS OF GENEROSITY Classy, a GoFundMe company, is a Public Benefit Corporation and giving platform that enables nonprofits to connect supporters with the causes they care about. Through technology, we empower nonprofits to unlock the generosity of their supporters and help them advance their missions. NONPROFIT RESOURCES Our team curates a library of resources with your success in mind. ・Blog - Fundraising and marketing best practices, industry trends, and more ・Webinars - On-demand access to insights from industry leaders ・Reports - The latest data on industry trends, giving behavior, and more. CLASSY CULTURE As part of the GoFundMe family, working at Classy is a unique and fulfilling experience where team members learn, create, and flourish with a group of passionate technologists working to mobilize and empower the world for good. PART OF THE GOFUNDME FAMILY Together, Classy and GoFundMe are a global giving platform that supports the largest giving community in the world. CLASSY AWARDS 2024 dates to be announced soon. Celebrating the impact of innovative nonprofits. The Classy Awards recognize nonprofits for their unique approaches and impact on our world. Winners are selected through a comprehensive evaluation process by a leadership council, a prestigious group of social sector leaders and executives. COLLABORATIVE BY CLASSY May 15-16, 2024 | Chicago Join other forward-thinking nonprofit leaders for this two-day conference that will uncover the ideas and strategies needed to propel our industry forward and help you raise more.

Classy.org

HackerNoon, the independent technology publishing platform, is pleased to announce the nominees for its annual “Startups of the Year” award, featuring the most promising and innovative companies in the San Diego startup ecosystem. San Diego, CA - May 24, 2023 - https://www.youtube.com/watch?v=ZqIW54yMsNc&embedable=true The list, compiled by the HackerNoon team, showcases that are making significant contributions to the San Diego economy and driving innovation in their respective industries. 133 startups The nominated for Startups of the Year 2023 include: Startups in San Diego GoFormz Lively Root Platform Science Kahoona Tag-N-Trac Launch Factory comma Zoox Streamlined Robin Healthcare KÉXY ChargeNet Stations Replay RobustPhysics Sensorydata Skillmasters.io Truepic Blueboard 6Storage XRA Lawmatics Brain Doctible Classy.org Helix GoShare Sportidia The Good Face Project Cloudbeds ClickUp You can nominate your company as the . startup of the year in San Diego here “We are thrilled to recognize the top startups in San Diego and celebrate their achievements,” said . “Starting and sustaining a company is difficult. We’re honored to showcase their work and impact.” David Smooke, HackerNoon Founder & CEO is a community-driven voting platform that recognizes startups that are changing technology and the world for the better. Starting May 8th, 2023, the internet can nominate and vote for the best ventures in their city. The voting period will remain open until December 31, 2023, and winners will be announced in January 2024 after a comprehensive evaluation by the HackerNoon team. Startups of the Year 2023 In its , a total of 44,427 startups were nominated in 16 different regions, and the community cast 234,344 votes during a 6-month long campaign in favor of budding companies that were growing and trending across every major city in the world. The received perks from sponsors and a free from HackerNoon. previous iteration 1,382 winners tech company news page As a proponent of the open data movement, HackerNoon releases the unique social data gathered from Startups of the Year on GitHub as “ ” for valuable insights. /where-startups-trend Apart from validation from the world's greenest tech publication, all nominees relevant to their domain, region, and funding. They will also receive an and a free version of their very own on HackerNoon. get free interviews amazing discount package designed for their startup Tech Company News Page These pages include business overviews (such as head count, founding year, bio, social links, and domain ranking) coupled with dynamic updates every time the company is mentioned in HackerNoon stories or relevant headlines around the web. People can , and vote once per day per award for who they think should be Startup of the Year all the way up to December 31st. nominate their favorite startups until June 8th In addition to the award itself, winners receive exclusive interviews, an exclusive NFT from HackerNoon, and a .Tech Domain for life. For more information about the “Startups of the Year 2023” list and the nominated companies, please visit our . FAQ page About HackerNoon HackerNoon is a technology publication that aims to empower developers, entrepreneurs, and tech enthusiasts to share their knowledge and expertise with a global audience. With millions of monthly readers, over 500,000 followers on social media, and over 250,000 newsletter subscribers, HackerNoon provides a platform for startups and innovators to showcase their work and connect with a vibrant community of like-minded individuals. Did you know that companies that actively engage in blogging experience a whopping 67% increase in leads? Take advantage of HackerNoon's ' ' to kickstart your own company's blogging journey. Startups Package Startups Of The Year 2023 is sponsored by . .Tech Domains You can nominate your company as the . startup of the year in San Diego here

Startups of The Year 2023: 130+ Startups Nominated in San Diego

Using Arrow Flight SQL Protocol in Apache Doris 2.1 For Super Fast Data Transfer

Education is easy when it is fun! No one says “no” to a little fun. That’s what Blooket is all about. It’s an online app that allows you to learn and play using limited tokens (coins) once you join. But hey, there are legit Blooket hacks to enjoy unlimited play. Table of Content All There is to Know about Blooket Key Features of Blooket How to Join a Blooket How to Host a Blooket Game Blooket Hack for Tokens Unlimited Token Blooket Hacks. Closing Note All There is to Know about Blooket Blooket is an online educational gaming platform that allows teachers to create and customize games for their students. The platform is designed to make learning engaging and fun, using game-based activities to reinforce educational concepts. Although designed as an academic resource, it is also a , so people can win prizes and exchange items or game-based gifts with other players. game Here are some key features and aspects of Blooket: Teachers can create their own games or use pre-existing templates to develop quizzes, flashcards, and other educational activities. These games can cover a wide range of subjects and topics. Game Creation: Blooket provides customization options, allowing teachers to tailor games to suit their specific curriculum and learning objectives. That includes adding images, audio, and video content to enhance the learning experience. Customization: : Games on Blooket are often played in a live setting, where students can join in real-time. It finds application in for in-class competitions or remote learning scenarios. Live Mode Besides live games, Blooket offers a solo mode that allows students to play games individually at their own pace. It can be useful for homework assignments or independent study. Solo Mode: Blooket provides analytics and reports to help teachers track student progress and identify areas where additional support may be needed. Reports and Analytics: Blooket aims to be accessible and user-friendly, making it suitable for various educational settings and grade levels. Accessibility: Although designed for teachers but not limited to teachers, users can create their own games, and other users or students can join. Games on Blooket are often played in “live” mode. How to Join a Blooket Game There are three major ways to join a Blooket: with an ID or with a link. Any of the methods allow you to play on your mobile phone or a PC. Join Blooket with a Game ID Step 1:
Click “Join a game” on the .
Step 2:
You will input a game ID, which only the game host can give. Then, enter the game. home page Join via a Link Alternatively, you can get a direct link from the host, which can be generated from their screen or dashboard. Once they share that with you, you can join the game directly. Join Blooket with a QR Code Another way is to get the game’s QR code with your phone, and it will let you into a game room. Smartphone cameras, these days, can connect you to the internet when automatically scanning a QR code. Once you join a game of Blooket to answer questions and compete, you will have to first input a nickname for identification. After that, you will have to choose an emoji to represent your nickname. This emoji is known as a “blook.” How to Host a Blooket Game While Blooket was created with education and educators in mind, you can also use it to have fun, play other games, and do more challenges. You can host challenges and complete ones hosted by others, and you can even trade some of your “blooks” for tokens. To host a game, you must log in. Once logged in, you can create a game by Go to your browser. Create a set of questions and answers. Go live by clicking “Host.” Blooket Hack for Tokens: Go to your browser. Create a set where all the answers are right. Host. Choose factory Set time to 10 minutes. Open another browser and join the game with the game ID or any of the other methods above. Play the game and try to answer as many questions as possible within the 10 minutes. Completing the game will give you token rewards for correct answers. While you play, try to get the best factory blooks. Good blooks mean better token rewards. The tip to get real easy token rewards is getting blooks from a good pack while you play. It is even better if you get blooks from the same clan. If you want even more rewards, you can set the game you’re hosting to about 15 minutes. If clicking for 10 minutes straight is tedious for you, you can try some auto-clicker tools. You may, as well, watch a show or movie while at it. Alternatively, Follow the same steps (1-3) as above. Then, Go into “Solo” and select ‘Cafe or Host a Game’ for a plus bonus. Set the time, and there you go. This method allows you to spam the questions as many times as possible. Steps: 1: Join the game ID 2: Start the game. 3: Spam questions because you get to answer many times, and that gets you token rewards. 4. Once answered, you can get honored as 1st place, with that, you get 500 tokens, which is the max possible for a day. Earning the first place will present you with the wheel spin. With that, you can win even more tokens. With that, you get and max out daily tokens. Comparing both the ‘Factory’ and ‘Cafe’ Options What makes the ‘Factory’ better is that your cursor can be in a spot, and you can automate your click or manually click from a spot. With the cafe, however, you still need to make some mouse movements to restock and choose your answers. Playing for tokens is legit and safe; there is no risk of getting blocked or banned for cheating. Blooket Hack with Code There is another hack that some folks use. These people get source codes that can locally modify their computer to automatically claim the maximum daily rewards possible (500 tokens and 300 XP). I consider this inappropriate, and that’s why it is not included in this article. Plus, there is the possibility of getting your account suspended or blocked. It spoils the fun and ruins the chance of playing the game for others. For classwork, if you randomly throw the tokens around without working with them, then the purpose of education is not fulfilled. Unlimited Tokens Blooket Hacks? You have probably seen ad hooks for a countless number of tokens while playing Blooket. Well, since inception until now, there has been no such thing as unlimited tokens on Blooket. There are no unlimited tokens on Blooket. So, any hack that promises unlimited tokens is untrue. What you can only have is the maximum number of tokens per day, which is 500 tokens, not including bonuses from spinning a wheel. Closing Note Blooket is a smart, educational innovation. For me, I think the design is mid, too basic, works for kids, and lacks action. However, I understand that the target audience includes school teachers and little pens. There is a maximum amount of 500 tokens that can be won daily. More tokens mean you can solve all quizzes without having to worry about getting logged out. Other similar educational tools include Kahoot and Quizlet, which have better displays and interfaces but neither require tokens nor have gaming options. You can read how and level the playground. Anybrain is using AI anti-cheat to catch game cheaters

Easy Blooket Hacks to Help You Play More Games and Get More Tokens

আপনাকে আরও গেম খেলতে এবং আরও টোকেন পেতে সাহায্য করার জন্য সহজ ব্লুকেট হ্যাক

Einfache Blooket-Hacks, die Ihnen helfen, mehr Spiele zu spielen und mehr Token zu erhalten

Trucos sencillos de Blooket para ayudarte a jugar más juegos y obtener más tokens

Des astuces Blooket faciles pour vous aider à jouer à plus de jeux et à obtenir plus de jetons

अधिक गेम खेलने और अधिक टोकन प्राप्त करने में आपकी सहायता के लिए आसान ब्लूकेट हैक्स

より多くのゲームをプレイしてより多くのトークンを入手するのに役立つ簡単な Blooket ハック

더 많은 게임을 플레이하고 더 많은 토큰을 얻는 데 도움이 되는 쉬운 Blooket 해킹

Easy Blooket Hacks para ajudá-lo a jogar mais jogos e obter mais tokens

Простые хаки Blooket, которые помогут вам играть в больше игр и получать больше жетонов

Daha Fazla Oyun Oynamanıza ve Daha Fazla Jeton Kazanmanıza Yardımcı Olacak Kolay Blooket Tüyoları

Mẹo Blocket dễ dàng giúp bạn chơi nhiều trò chơi hơn và nhận được nhiều token hơn

简单的 Blooket 黑客可帮助您玩更多游戏并获得更多代币

In this article, we will see how can we perform operations with database using JDBC. We will then cover how to create a table in MySQL database and how to insert, update, and delete the rows using the JDBC program. crud MySQL You can find a video below with my step-by-step process. youtube https://www.youtube.com/watch?v=fUBoDErcDHA&embedable=true&transcript=true Let’s dive straight into the code Insert Class import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class Insert {
    public static void main(String[] args) {
        //load the driver
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        try (Connection con = DriverManager.getConnection("jdbc:mysql://@localhost:3306/new_schema", "root", "root"); Statement st = con.createStatement();) {
            String query = "INSERT INTO EMP(EID,ENAME) values(1,'Ram')";
            int count = st.executeUpdate(query);
            if (count == 0) {
                System.out.println("Record not inserted");
            } else {
                System.out.println("Record Inserted");
            }
        } catch (SQLException se) {
            se.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
} Delete Class import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class Delete {
    public static void main(String[] args) {
        // load the driver
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        try (Connection con = DriverManager.getConnection("jdbc:mysql://@localhost:3306/new_schema", "root", "root"); Statement st = con.createStatement();) {
            String query = "DELETE FROM EMP WHERE EID=1";
            int count = st.executeUpdate(query);
            if (count != 0) {
                System.out.println("Record Deleted");
            } else {
                System.out.println("Record Not Deleted");
            }
        } catch (SQLException se) {
            se.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
} Update Class import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class Update {
    public static void main(String[] args) {
        // load the driver
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        try (Connection con = DriverManager.getConnection("jdbc:mysql://@localhost:3306/new_schema", "root", "root"); Statement st = con.createStatement();) {
            String query = "UPDATE EMP SET ENAME='SAM' WHERE EID=1";
            int count = st.executeUpdate(query);
            if (count != 0) {
                System.out.println("Record UPDATED");
            } else {
                System.out.println("Record Not UPDATED");
            }
        } catch (SQLException se) {
            se.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
} /Select Class import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class Select {
    public static void main(String[] args) {
        // load the driver
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        try (Connection con = DriverManager.getConnection("jdbc:mysql://@localhost:3306/new_schema", "root", "root"); Statement st = con.createStatement();) {
            String query = "SELECT EID,ENAME FROM EMP";
            ResultSet rs = st.executeQuery(query);
            while (rs.next()) {
                System.out.println(rs.getInt(1) + " " + rs.getString(2));
            }
        } catch (SQLException se) {
            se.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
} The lead image for this article was generated by HackerNoon's AI Image Generator via the prompt "database".

Mastering Java JDBC CRUD Operations in Eclipse Using MySQL

The term "metaverse" has been a buzzword used throughout the tech industry for some time now, with everyone from gamers to investors scrambling to learn more about the potential of this new digital environment. However, the has impacts far beyond entertainment and commerce. metaverse Metaverse has the potential to revolutionize the way we approach education. Beyond virtual chat rooms and video games, the digital worlds of the metaverse can transport students to places they could have never imagined visiting through the power of virtual reality (VR) and augmented reality (AR) technology. From the ocean's depths to the surface of Mars, the possibilities the metaverse unlocks for truly immersive learning are seemingly boundless. Through these immersive experiences, students can enhance their understanding of complex concepts and help them retain information more effectively. that immersive technologies such as VR can improve memory recall, increase motivation, and improve classroom engagement in learners. For those who struggle with traditional classroom learning, these new technologies can give students a new way to succeed. Research has shown That means a more accessible and inclusive learning experience for all. The traditional classroom model doesn't work for everyone. The widening gap in student learning abilities combined with expanding class sizes across the country makes it challenging for teachers to provide a more typical, inclusive learning environment. The metaverse can offer a different and more inclusive approach by enabling students to participate in a virtual learning environment tailored to their needs. Students in rural or underserved areas who might not have access to specialized resources or high-quality education will also see benefits. Within the metaverse, these students can access the same high-quality content and experiences as students in more affluent areas, bridging the growing digital divide. However, the metaverse isn't only about the individual; it also offers opportunities for social connection and teamwork. Collaboration is the core component of many existing metaverse experiences, with users working together to solve puzzles, complete challenges, and build virtual worlds. Inside the classroom, students can collaborate on group projects, share ideas, and learn from one another. Beyond classwork, students can also develop essential social and emotional skills such as communication, teamwork, and problem-solving. These experiences help kids feel more connected to one another, which, in turn, can translate to them being more active in their communities and achieving higher academic success. The metaverse also has its challenges regarding education. The demand for infrastructure and technology support is among the main challenges the metaverse poses to schools. Schools must make the required hardware and software investments to construct and access the metaverse, which can become expensive depending on district sizes. With growing teacher shortages and tightening budgets, some schools need more resources to allocate to this technology. Additionally, a digital divide initially meant to be solved could be strained due to students needing the means or skills to use the equipment required at home. Finding qualified teachers who can use the metaverse effectively may still present its challenge, even with adequate resources. Teachers will need the training to develop a curriculum, promote learning, and control student behavior in virtual and conventional classrooms. A sizable investment in teacher development, training, and continued support is also necessary to guarantee that educators have the knowledge and tools they need to thrive. Finally, concerns about safety and may keep some educators on edge. Similar to any device connected to the Internet, the metaverse is susceptible to cyberbullying, harassment, and other types of online abuse. Schools must create policies and processes to safeguard their students online and stay up with and continually revise them based on these evolving digital environments. privacy within the metaverse Despite these challenges, the positive impact of the metaverse in education is almost impossible to ignore. By providing an immersive, inclusive, and collaborative learning experience, the metaverse can transform education and provide students with a learning experience that's (quite literally) out of this world. As technology evolves, parents, educators, administrators, and policymakers must remain on top of technological advancements and consider the opportunities the metaverse presents for education. Fortunately, there are a lot of pilot projects and partnerships that make it easy to integrate the metaverse into the classroom. Companies like can assist in bridging the technology and education divide and give students the skills they need to flourish in the digital era by collaborating with schools and other educational institutions. Tynker Ultimately, the metaverse is just one part of the growing toolkit of the modern educator. The challenge is ensuring that all key stakeholders, from policymakers, educators, parents, and   firms, can partner well. Through this collaboration, we can create a more immersive, inclusive, and collaborative learning experience that prepares students for success in the 21st century. Are you ready to plug in? About the Author is the Chief Growth Officer of Tynker, with 20 years of experience helping startups grow into successful businesses. Lomit Patel Lomit has previously played a critical role in scaling growth at startups, including Roku (IPO), TrustedID (acquired by Equifax), Texture (acquired. by Apple), and IMVU (#2 top-grossing gaming app). Lomit is a public speaker, author, and advisor with numerous accolades and awards throughout his career, including being recognized as a Mobile Hero by Liftoff. Lomit's book is part of Eric Ries' best-selling "The Lean Startup" series. Lean AI

The Potential Impact of the Metaverse on Education

El impacto potencial del metaverso en la educación

L'impact potentiel du métaverse sur l'éducation

शिक्षा पर मेटावर्स का संभावित प्रभाव

教育に対するメタバースの潜在的な影響

O impacto potencial do metaverso na educação

Tác động tiềm ẩn của Metaverse đối với giáo dục

元宇宙对教育的潜在影响

Welcome to other chapters of Let’s Understand Chrome V8 Dispatch is responsible for scheduling bytecode, which is equivalent to registering EIP++, and jumps to the next bytecode. Dispatch consists of two parts, one is a dispatch table and the other is the physical register. The table is an array that contains all bytecode addresses. V8 uses the physical register to dispatch bytecode for getting greater efficiency. 1. Dispatch Table The dispatch table is an array of pointers, which is used to store the address of the bytecode processing program. The array type is Code, and the Code Class is below: class Code: public HeapObject {
    public: NEVER_READ_ONLY_SPACE
    using Flags = uint32_t;
    #define CODE_KIND_LIST(V)\
    V(OPTIMIZED_FUNCTION)\
    V(BYTECODE_HANDLER)\
    V(STUB)\
    V(BUILTIN)\
    V(REGEXP)\
    V(WASM_FUNCTION)\
    V(WASM_TO_CAPI_FUNCTION)\
    V(WASM_TO_JS_FUNCTION)\
    V(JS_TO_WASM_FUNCTION)\
    V(JS_TO_JS_FUNCTION)\
    V(WASM_INTERPRETER_ENTRY)\
    V(C_WASM_ENTRY)
    enum Kind {
      #define DEFINE_CODE_KIND_ENUM(name) name,
        CODE_KIND_LIST(DEFINE_CODE_KIND_ENUM)
      #undef DEFINE_CODE_KIND_ENUM
      NUMBER_OF_KINDS
    };
    static
    const char * Kind2String(Kind kind);
    #ifdef ENABLE_DISASSEMBLER
    const char * GetName(Isolate * isolate) const;
    V8_EXPORT_PRIVATE void Disassemble(const char * name, std::ostream & os,
      Address current_pc = kNullAddress);
    #endif
    //................omit................
  }; : In the isolate, there is another pointer array that is the same type as the dispatch table. It holds all the Builtins addresses, which can confuse beginners easily. Note The dispatch table is maintained by BuildWithMacroAssembler, code is below: Code BuildWithMacroAssembler(Isolate * isolate, int32_t builtin_index,
    MacroAssemblerGenerator generator,
    const char * s_name) {
    HandleScope scope(isolate);
    // Canonicalize handles, so that we can share constant pool entries pointing
    // to code targets without dereferencing their handles.
    CanonicalHandleScope canonical(isolate);
    constexpr int kBufferSize = 32 * KB;
    byte buffer[kBufferSize];
    MacroAssembler masm(isolate, BuiltinAssemblerOptions(isolate, builtin_index),
      CodeObjectRequired::kYes,
      ExternalAssemblerBuffer(buffer, kBufferSize));
    masm.set_builtin_index(builtin_index);
    DCHECK(!masm.has_frame());
    generator( & masm);
    int handler_table_offset = 0;
    // JSEntry builtins are a special case and need to generate a handler table.
    DCHECK_EQ(Builtins::KindOf(Builtins::kJSEntry), Builtins::ASM);
    DCHECK_EQ(Builtins::KindOf(Builtins::kJSConstructEntry), Builtins::ASM);
    DCHECK_EQ(Builtins::KindOf(Builtins::kJSRunMicrotasksEntry), Builtins::ASM);
    if (Builtins::IsJSEntryVariant(builtin_index)) {
      handler_table_offset = HandlerTable::EmitReturnTableStart( & masm);
      HandlerTable::EmitReturnEntry( &
        masm, 0, isolate -> builtins() -> js_entry_handler_offset());
    }
    //.....................................................
    //................omit.............................
  } You can see regarding how to debug the BuildWithMacroAssembler. When the value of the parameter builtin_index is 65, the function pointer generator points to which is responsible for maintaining the Dispatch table, code is below: Chapter 9 Generate_InterpreterEnterBytecodeDispatch static void Generate_InterpreterEnterBytecode(MacroAssembler * masm) {
    // Set the return address to the correct point in the interpreter entry
    // trampoline.
    Label builtin_trampoline, trampoline_loaded;
    Smi interpreter_entry_return_pc_offset(
      masm -> isolate() -> heap() -> interpreter_entry_return_pc_offset());
    DCHECK_NE(interpreter_entry_return_pc_offset, Smi::kZero);
    // If the SFI function_data is an InterpreterData, the function will have a
    // custom copy of the interpreter entry trampoline for profiling. If so,
    // get the custom trampoline, otherwise grab the entry address of the global
    // trampoline.
    __ movq(rbx, Operand(rbp, StandardFrameConstants::kFunctionOffset));
    __ LoadTaggedPointerField(
      rbx, FieldOperand(rbx, JSFunction::kSharedFunctionInfoOffset));
    __ LoadTaggedPointerField(
      rbx, FieldOperand(rbx, SharedFunctionInfo::kFunctionDataOffset));
    __ CmpObjectType(rbx, INTERPRETER_DATA_TYPE, kScratchRegister);
    __ j(not_equal, & builtin_trampoline, Label::kNear);
    __ movq(rbx,
      FieldOperand(rbx, InterpreterData::kInterpreterTrampolineOffset));
    __ addq(rbx, Immediate(Code::kHeaderSize - kHeapObjectTag));
    __ jmp( & trampoline_loaded, Label::kNear);
    __ bind( & builtin_trampoline);
    // TODO(jgruber): Replace this by a lookup in the builtin entry table.
    __ movq(rbx,
      __ ExternalReferenceAsOperand(
        ExternalReference::
        address_of_interpreter_entry_trampoline_instruction_start(
          masm -> isolate()),
        kScratchRegister));
    __ bind( & trampoline_loaded);
    __ addq(rbx, Immediate(interpreter_entry_return_pc_offset.value()));
    __ Push(rbx);
    // Initialize dispatch table register.
    __ Move(
      kInterpreterDispatchTableRegister,
      ExternalReference::interpreter_dispatch_table_address(masm -> isolate()));
    // Get the bytecode array pointer from the frame.
    __ movq(kInterpreterBytecodeArrayRegister,
      Operand(rbp, InterpreterFrameConstants::kBytecodeArrayFromFp));
    if (FLAG_debug_code) {
      // Check function data field is actually a BytecodeArray object.
      __ AssertNotSmi(kInterpreterBytecodeArrayRegister);
      __ CmpObjectType(kInterpreterBytecodeArrayRegister, BYTECODE_ARRAY_TYPE,
        rbx);
      __ Assert(
        equal,
        AbortReason::kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
    }
    // Get the target bytecode offset from the frame.
    __ movq(kInterpreterBytecodeOffsetRegister,
      Operand(rbp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
    __ SmiUntag(kInterpreterBytecodeOffsetRegister,
      kInterpreterBytecodeOffsetRegister);
    // Dispatch to the target bytecode.
    __ movzxbq(r11, Operand(kInterpreterBytecodeArrayRegister,
      kInterpreterBytecodeOffsetRegister, times_1, 0));
    __ movq(kJavaScriptCallCodeStartRegister,
      Operand(kInterpreterDispatchTableRegister, r11,
        times_system_pointer_size, 0));
    __ jmp(kJavaScriptCallCodeStartRegister);
  }
  //================================separation=========================
  void Builtins::Generate_InterpreterEnterBytecodeDispatch(MacroAssembler * masm) {
    Generate_InterpreterEnterBytecode(masm);
  } In the above code, the is the entry point of bytecode dispatch, and the is the key code that implements the bytecode dispatch. Here are two important concepts: Generate_InterpreterEnterBytecodeDispatch Generate_InterpreterEnterBytecode The is a Builtin and its index is 65. (The index may be dissimilar in different V8 versions) Generate_InterpreterEnterBytecodeDispatch V8 uses a physical register to manage the dispatch table, the name of the register is . Using the physical register can avoid the push and pop of the dispatch table frequently, to improve efficiency. kInterpreterDispatchTableRegister Here are the key lines of code： Line 35, loads the dispatch table to the A register. Line 37 of code, take out the table address from the isolate. The implementation of A is in the below three functions. (1) ExternalReference ExternalReference::interpreter_dispatch_table_address(
  Isolate * isolate) {
  return ExternalReference(isolate -> interpreter() -> dispatch_table_address());
}
interpreter::Interpreter * interpreter() const {
  return interpreter_;
}
Address dispatch_table_address() {
  return reinterpret_cast < Address > ( & dispatch_table_[0]);
} Line 39 takes out the bytecode array from the stack. (2) Line 51 takes out the offset of the target bytecode from the bytecode array. (3) Lines 56 and 58 calculate the target bytecode address and store the address in kJavaScriptCallCodeStartRegister. (4) Line 61 jumps to register kJavaScriptCallCodeStartRegister and executes bytecode. Figure 1 is the call stack. (5) 2. TailCall The Dispatch() is the last step in a bytecode, so its alias is the tail call. Let’s look at a few bytecodes： IGNITION_HANDLER(StaGlobal, InterpreterAssembler) {
    TNode < Context > context = GetContext();
    //omit..............
    Goto( & end);
    Bind( & no_feedback);
    CallRuntime(Runtime::kStoreGlobalICNoFeedback_Miss, context, value, name);
    Goto( & end);
    Bind( & end);
    Dispatch(); // !!! this is the tail call.
  }
  IGNITION_HANDLER(LdaContextSlot, InterpreterAssembler) {
    TNode < Context > context = CAST(LoadRegisterAtOperandIndex(0));
    TNode < IntPtrT > slot_index = Signed(BytecodeOperandIdx(1));
    TNode < Uint32T > depth = BytecodeOperandUImm(2);
    TNode < Context > slot_context = GetContextAtDepth(context, depth);
    TNode < Object > result = LoadContextElement(slot_context, slot_index);
    SetAccumulator(result);
    Dispatch(); //!!! here also is.
  }
  IGNITION_HANDLER(LdaImmutableContextSlot, InterpreterAssembler) {
    TNode < Context > context = CAST(LoadRegisterAtOperandIndex(0));
    TNode < IntPtrT > slot_index = Signed(BytecodeOperandIdx(1));
    TNode < Uint32T > depth = BytecodeOperandUImm(2);
    TNode < Context > slot_context = GetContextAtDepth(context, depth);
    TNode < Object > result = LoadContextElement(slot_context, slot_index);
    SetAccumulator(result);
    Dispatch(); //!!! here 
  } The above three bytecodes all end with Dispatch(). Below is the code of Dispatch: void InterpreterAssembler::Dispatch() {
    Comment("========= Dispatch");
    DCHECK_IMPLIES(Bytecodes::MakesCallAlongCriticalPath(bytecode_), made_call_);
    TNode < IntPtrT > target_offset = Advance();
    TNode < WordT > target_bytecode = LoadBytecode(target_offset);
    if (Bytecodes::IsStarLookahead(bytecode_, operand_scale_)) {
      target_bytecode = StarDispatchLookahead(target_bytecode);
    }
    DispatchToBytecode(target_bytecode, BytecodeOffset());
  } The 2nd line is the comment function. When debugging, we can use its output information to locate the execution position. The 4th line takes out the offset of the target(next) bytecode. The 5th line loads the target bytecode. The 9th line calls which calls eventually. DspatchToBytecode() DispatchToBytecodeHandlerEntry() void InterpreterAssembler::DispatchToBytecodeHandlerEntry(
  TNode < RawPtrT > handler_entry, TNode < IntPtrT > bytecode_offset) {
  // Propagate speculation poisoning.
  TNode < RawPtrT > poisoned_handler_entry =
    UncheckedCast < RawPtrT > (WordPoisonOnSpeculation(handler_entry));
  TailCallBytecodeDispatch(InterpreterDispatchDescriptor {},
    poisoned_handler_entry, GetAccumulatorUnchecked(),
    bytecode_offset, BytecodeArrayTaggedPointer(),
    DispatchTablePointer());
} In , parameter 1 is the target bytecode and 2 is the offset of the bytecode. Parameter 1 is used to load the bytecode handler and 2 is used to load operands. Then call , which is below: DispatchToBytecodeHandlerEntry TailCallBytecodeDispatch template < class...TArgs >
    void CodeAssembler::TailCallBytecodeDispatch(
      const CallInterfaceDescriptor & descriptor, TNode < RawPtrT > target,
        TArgs...args) {
      DCHECK_EQ(descriptor.GetParameterCount(), sizeof...(args));
      auto call_descriptor = Linkage::GetBytecodeDispatchCallDescriptor(
        zone(), descriptor, descriptor.GetStackParameterCount());
      Node * nodes[] = {
        target,
        args...
      };
      CHECK_EQ(descriptor.GetParameterCount() + 1, arraysize(nodes));
      raw_assembler() -> TailCallN(call_descriptor, arraysize(nodes), nodes);
    } In the above code, the 5th line creates the descriptor, as below: CallDescriptor * Linkage::GetBytecodeDispatchCallDescriptor(
    Zone * zone,
    const CallInterfaceDescriptor & descriptor,
      int stack_parameter_count) {
    const int register_parameter_count = descriptor.GetRegisterParameterCount();
    const int parameter_count = register_parameter_count + stack_parameter_count;
    DCHECK_EQ(descriptor.GetReturnCount(), 1);
    LocationSignature::Builder locations(zone, 1, parameter_count);
    locations.AddReturn(regloc(kReturnRegister0, descriptor.GetReturnType(0)));
    for (int i = 0; i < parameter_count; i++) {
      if (i < register_parameter_count) {
        // The first parameters go in registers.
        Register reg = descriptor.GetRegisterParameter(i);
        MachineType type = descriptor.GetParameterType(i);
        locations.AddParam(regloc(reg, type));
      } else {
        int stack_slot = i - register_parameter_count - stack_parameter_count;
        locations.AddParam(LinkageLocation::ForCallerFrameSlot(
          stack_slot, MachineType::AnyTagged()));
      }
    }
    MachineType target_type = MachineType::Pointer();
    LinkageLocation target_loc = LinkageLocation::ForAnyRegister(target_type);
    const CallDescriptor::Flags kFlags =
      CallDescriptor::kCanUseRoots | CallDescriptor::kFixedTargetRegister;
    return new(zone) CallDescriptor( // --
      CallDescriptor::kCallAddress, // kind
      target_type, // target MachineType
      target_loc, // target location
      locations.Build(), // location_sig
      stack_parameter_count, // stack_parameter_count
      Operator::kNoProperties, // properties
      kNoCalleeSaved, // callee-saved registers
      kNoCalleeSaved, // callee-saved fp
      kFlags, // flags
      descriptor.DebugName());
  } In , parameter 2 is the target bytecode, and parameter 3 is the stack parameter count. This function is used to apply for register resources and create a . The gives what parameters to supply when executing a bytecode. The comments on lines 24 to 25 give its layout. GetBytecodeDispatchCallDescriptor CallDescriptor CallDescriptor In , the on the 9th line is below, we see that it’s parameter 1 is . TailCallBytecodeDispatch TailCallN() CallDescriptor void RawMachineAssembler::TailCallN(CallDescriptor * call_descriptor,
    int input_count, Node *
    const * inputs) {
    // +1 is for target.
    DCHECK_EQ(input_count, call_descriptor -> ParameterCount() + 1);
    Node * tail_call =
      MakeNode(common() -> TailCall(call_descriptor), input_count, inputs);
    schedule() -> AddTailCall(CurrentBlock(), tail_call);
    current_block_ = nullptr;
  } The 5th line generates a node. In the 7th line adds the node to the end of the current basic block. So far, the dispatch is completed and the next bytecode is started to execute. Figure 2 shows the function call stack. AddTailCall() Okay, that wraps it up for this share. I’ll see you guys next time, take care! Please reach out to me if you have any issues. : qq9123013 : v8blink@outlook.com WeChat Email Also published . here

Let's Understand Chrome V8 — Chapter 11: Bytecode Dispatch 

WorkManager is ubiquitous in modern android development. We use it to run any background work which should not be bound to the application process lifecycle. It was first introduced in May 2018 and replaced several scheduling frameworks. The library unifies it all with a concise and simple API. You no longer have to orchestrate JobScheduler, GcmNetworkManager, Evernote AndroidJob, and so on. In fact, this new API is saving us quite a lot of maintenance work, but is it perfect? There are a few rough areas we’ll explore in this article. Dependency injection It’s hard to imagine a modern production-grade android application without dependency injection. In our example, we’ll use Dagger2, but the principle will remain the same for any DI framework. Consider that you have a job that runs every hour. Its purpose is to delete old telemetry records from an SQLite database. The naive approach would be to create a component inside the worker and call : inject class CleanTelemetryWorker(context: Context, params: WorkerParameters) : Worker(context, params) {

    @Inject
    lateinit var telemetryRepository: TelemetryRepostory

    init {
        CleanTelemetryWorkerComponent.Factory.create(context).inject()
    }

    override fun doWork(): ListenableWorker.Result {
        telemetryRepository.clean()
    }
} This solution is not ideal for a few reasons: The dependency inversion principle breaks since the component should not know how to get its dependencies This worker is hard to test because there’s no easy way to mock dependencies, but we’ll get to it later What we want is to be able to declare any worker like this: class CleanTelemetryWorker @Inject constructor(
        context: Context, 
        params: WorkerParams,
        telemetryRepository: TelemetryRepository,
        ...//any other external dependencies
) Can we do better? We can! As you may know, we can customize WorkManager using the class: Configuration class MyApplication() : Application(), Configuration.Provider {
     override fun getWorkManagerConfiguration() =
           Configuration.Builder()
                .setMinimumLoggingLevel(android.util.Log.INFO)
                .setWorkerFactory(myCustomWorkerFactory)
                .build()
} You override in your class and provide a config object. The most important part here is the method. It allows us to pass a component that will create jobs for us. It sounds like the ideal place to inject our dependencies into workers. getWorkManagerConfiguration Application setWorkerFactory has only one method we can override, and it’s called… : WorkerFactory createWorker class CustomWorkerProvider {
    override createWorker(appContext: Context, 
                          workerClassName: String, 
                          workerParameters: WorkerParameters): ListenableWorker? {
        //We need to provide workers here. 
    } 
} Now we can provide arguments into our worker’s constructor. Fortunately, we don't have to do it ourselves. There exists this handy tool to generate dependency provision for us called Dagger 2. Let’s try to create a simple and robust schema to inject dependencies into workers. Of course there’s plenty of ways to do this, but let’s start simple and then add some options to it as we go. So what exactly do we need to create a worker? The class has two required dependencies: and . Let’s start with the dagger component that we will init in the function. ListenableWorker Context WorkerParameters WorkerComponent createWorker @Component
interface WorkerComponent {
    @Component.Factory
    interface Factory {
        fun create(
          @BindsInstance context: Context,
          @BindsInstance workerParameters: WorkerParameters,
        ): WorkerComponent
    }
} We use annotation to tell dagger to create an implementation of which will return us the implementation. Component.Factory WorkerComponent.Factory WorkerComponent annotation in the factory’s method means that this component should be able to provision and using the objects we passed to the method. @BindsInstance create Context WorkParameters Cool, we can now provide workers by adding a method that returns a concrete worker class, like CleanTelemetryWorker @Component(dependencies=[ApplicationComponent::class])
interface WorkerComponent {

   @Component.Factory
   interface Factory {
        fun create(
          applicationComponent: ApplicationComponent,
          @BindsInstance context: Context,
          @BindsInstance workerParameters: WorkerParameters,
        ): WorkerComponent
   }

   fun cleanTelemetryWorker(): CleanTelemetryWorker
...
} Notice that we need to add dependencies to the component’s annotation because by itself can’t provide you with anything other than and . We also have to pass the dependency component as a factory argument. WorkerComponent Context WorkerParameters Let’s see how the will look like now: CustomWorkerProvider class CustomWorkerProvider(private val applicationComponent: ApplicationComponent) {
    override createWorker(appContext: Context, 
                          workerClassName: String, 
                          workerParameters: WorkerParameters): ListenableWorker? {
        val component = DaggerWorkerComponent.factory().create(applicationComponent, appContext, workerParameters)
        when(workeClassName) {
          ClientTelemetryWorker::class.qualifiedName -> component.cleanTelemetryWorker()
          ...
        }
    } 
} It looks much better, but every time we add a new worker, we have to provide it here and add a new function definition to the component. Can dagger2 help us with this? Dagger Multibinding! With dagger multi binding, we can declare a module for each worker which will provide a worker provider in a map, where keys are the java classes of the workers. @Module
interface CleanTelemetryWorkerModule {
    @Binds
    @IntoMap
    @ClassKey(CleanTelemetryWorker::class.java)
    fun bindCleanTelemetryWorker(cleanTelemetryWorkerProvider: Provider<CleanTelemetryWorker>): Provider<out ListenableWorker>
} Let’s add this module to the component: @Component(dependencies=[ApplicationComponent::class], 
           modules=[CleanTelemetryWorkerModule::class],)
interface WorkerComponent {
    ...
} And finally, our will look like this: CustomWorkerProvider class CustomWorkerProvider(private val applicationComponent: ApplicationComponent) {
    override createWorker(appContext: Context, 
                          workerClassName: String, 
                          workerParameters: WorkerParameters): ListenableWorker? {
        val component = DaggerWorkerComponent.factory().create(applicationComponent, appContext, workerParameters)
        val workerProvidersMap = component.workerProvidersMap()
        return workerProvidersMap[Class.forName(workerClassName)]!!.get()
    } 
} Every time you have to add a new job, you’ll only have to create a new module and attach it to the . Neat, right? WorkerComponent Why does it matter, after all? The jobs now look like any other class with externally declared dependencies. It allows us to enforce the dependency inversion principle of SOLID.
With the relatively small overhead, we achieve the following benefits: Testability We can mock job dependencies or pass different implementations at any time. Jobs are not aware of the dependency inversion framework. If you choose to switch from Dagger 2 to any other DI framework, your jobs will remain the same. The only thing that will change is the external glue. Ease of support Reducing mental stress on the developers is also a thing. Previously every time you created a job, you had to think about how to get your dependencies there. It’s not always trivial, especially if your dependency graph has different scopes. In the following article, we’ll reap the benefits of this setup and explore how to properly test your workers now that we have an easy way to mock the dependencies. I hope this article was helpful! Let me know what you think :)

How to Cook WorkManager with Dagger 2

I am a big fan of leet code so when we decided to have a code challenge in our team I thought it wouldn’t be a bad idea to build one which should include pretty basic functionalities like: Ability to register and sign in to the application Present the problem (questions) Provide an interface for the end-users to write, compile and execute code. Overall, it was an amazing learning experience and I am happy to walk through how I did it. Guidelines Before I start working on this I decided to come up with some guidelines so I don't over-engineer this and end up building a Frankenstein out of it, here are few of those guidelines: The whole system should be implemented in 3 to 4 days Reuse as much as you can when it comes to technology or service. build anything new unless until it doesn't exist DON'T standing cost for the infrastructure. Pay for what you use and pay as you can ZERO ONLY MINIMAL Technologies & Runtime Services + JQuery (UI) Bootstrap AWS Lambda AWS API Gateway AWS Dynamodb AWS Dynamodb streams AWS Simple email service (SES) AWS S3 (For static site hosting) High-level Architecture The system consists of four keys functionalities based on which these modules are designed: Registration & sign-in Compile & Execute Score Calculator Winner Predictor Registration & Sign-in Flow We have a single lambda function that takes care of registering a new user and authenticating an existing user in the application. Part of registration flow user enters “FirstName”, “LastName” & “Email address” which is passed in as “QueryParam” to API gateway. Gateway invokes a Lambda function which takes care of saving the user details in DynamoDb, generating a random registration code (UUID based) and sending it in an email to the registered email address The sign-in flow will authenticate the user with the passed in email address and UUID using the Lambda function Compile & Execute When the user submits the code, the web application will call the API gateway with the following parameters: QuestionsId User types code Registration code API gateway will invoke the lambda function which will get information about the question/problem statement from the “Questions” table in Dynamodb (data looks like below). From the table data, we take the “GeneratedCode” attribute value and replace various tokens like — name — , — codeworking — & — testcases — with the class name (generated), the user typed code, and test cases (from columns “Test_1”… “Test_N”). Here is how the replaced code will look: { { { count= ; index= ; ( ){ {
                  s.charAt(index++);
                  count++;
              } (Exception e){ ;
              }
          } count;
      }
   } { actual= ; expected = ;
        String input = ; input = ;
        expected = ;
        actual = Solution.calculate(input); actual == expected :  String.format( , input, expected, actual);
    }
} // --name-- public class f_sdsds_a11223_dd // --codeworking-- static class Solution public static int calculate (String s) int 0 int 0 while true try catch break return public static void main (String args[]) int 0 int 3 null // --testcases-- "Hi1" 3 assert "--helper-- Input %s -> Expected = %s but got = %s" Since Lambda containers don't have JDK installed we have to package “tools.jar” inside the deployment package so we can run the compilation inside the containers, here is the code snippet on how we run compile inside lambda: (StringInputStream inputStream = StringInputStream(data);
     ByteArrayOutputStream outputStream = ByteArrayOutputStream();
     ByteArrayOutputStream errorOutputStream = ByteArrayOutputStream()) {
    Class<?> javacTool = Class.forName( );
    Method create = javacTool.getMethod( );
    JavaCompiler compiler = (JavaCompiler) create.invoke( );
    compiler.run(inputStream, outputStream, errorOutputStream, path.toFile().getAbsolutePath()); ProcessResponse(replaceNewLine(outputStream), replaceNewLine(errorOutputStream));
} (Exception e) { ProcessResponse( , + e.getMessage());
} try new new new "com.sun.tools.javac.api.JavacTool" "create" null return new catch return new null "Compilation error --> " If compilation is successful, we run the generated class which contains the test cases. java -ea -cp /tmp/f_sdsds_a11223_dd If execution is successful without any assertion failures, execution time is stored in “UserSubmission” table. Score Calculator We utilize DynamoDB streams to update the total points and total execution time for any given user. A lambda function listens to all updates done on “UserSubmission” table and performs these calculations once the submission is successful. Winner Predictor To find the winners, we run a simple query to get the top 3 rows in “UserStastics” table generated by sorting “TotalPoints” column in descending order and “TotalExecution” column in ascending Demo Here is the demo of the application: I know this doesn't solve all the use cases that a popular code challenge websites like “leetcode” or “topcoder” solves. But this is a good start & foundation which we can keep adding on. If you like this post then leave a comment. That way, I know you have made it all the way to the end 😀 . Thanks again for reading. Previously published at https://medium.com/javarevisited/build-code-challenge-application-23aa40d183fa

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