How I Prepared for OCP Java SE 11, 2021

Hi there! My name is Parviz. I would like to share my experience obtaining the coveted title of Oracle Certified Professional Java SE 11.

I also received a limited edition badge because I passed the exam during the promotion period until April 25, 2021!

Why do you need certification?

Do you need it at all?

The usefulness of professional certification is an oft-debated topic amongst professional developers. Some are convinced that a certificate is highly desirable to get a decent job. Others say that certificates do not play an important role, that even a higher education diploma may not be required - only skills and work experience matter.

Obtaining a qualification is a great way to structure your knowledge and delve deeper into the programming language (or database, cloud technologies, etc.).

About the path to certification

Previously, to get an OCP, you had to pass the OCA (Oracle Certified Associate). Fortunately, for Java 11, now you can immediately gain the OCP upon passing the 1Z0-819 - Java SE 11 Developer exam. In addition, the number of questions has changed; if earlier there were 80 questions in each exam and for this 150 minutes were allotted, now the exam is 90 minutes long and has 50 questions covering all topics from past exams, with a passing grade of 68%.

Most of the questions can have several correct answers. Now you have the option to take the exam from the comfort of your own home. In that case, you will be observed through the camera and microphone throughout the exam.

There should be no one in the room, you cannot talk to anyone and only look at the screen, and your internet connection must be stable, without interruptions. Otherwise, the exam is canceled. I chose the online option (and received two warnings during the exam).

Review of exam topics

Working with Java data types
Controlling Program Flow
Java Object-Oriented Approach
Exception Handling
Working with Arrays and Collections
Working with Streams and Lambda expressions
Java Platform Module System
Concurrency
Java IO & NIO API
Secure Coding in Java SE Application
Database Applications with JDBC
Localization
Annotations

You can find a more detailed topic list here.

I would like to draw your attention to the fact that I came across a lot of questions about data type, controlling flow, streams, lambdas, and functional interfaces. However, for other topics, there were only 1-2 questions.

Solve mock exams

You should also spend a lot of time taking mock exams. I bought mock exams from enthuware. They have a lot of useful functionality, including tests by topics, imitation of a real exam, notes, etc.

What questions you may encounter

Have a go at solving these problems. The answers will be at the end:

1. What will the following code print?

outer:
  for ( var i = 0 ; i<3 ; i++ ){
     for ( var j = 0 ; j<2 ; j++ ){
        if ( i == j ){
           continue outer;
        }
        System.out.println( "i=" + i + " , j=" + j );
     }
  }

2. What will the following code print when run?

Deque<Integer> d = new ArrayDeque<>();
 
d.add(1);
d.add(2);
d.addFirst(3);
 
System.out.println(d.pollLast());
System.out.println(d.pollLast());
System.out.println(d.pollLast());

3. What will the following code fragment print?

Path p1 = Paths.get("photos/goa"); 
Path p2 = Paths.get("/index.html");
Path p3 = p1.relativize(p2);
 
System.out.println(p3);

4. Given:

@Target({ElementType.LOCAL_VARIABLE, ElementType.FIELD, ElementType.METHOD}) //1
@Target({ElementType.TYPE})//2
@Retention(RetentionPolicy.RUNTIME)//3
public @interface DebugInfo { //4
   String name() default=""; //5
   String[][] params();//6
   java.util.Date entryTime();//7
}

Which line(s) will cause compilation failure?

5. Which of the following interface definitions can use Lambda expressions?

//1
interface A{
}
 
//2
interface A{
   default void m(){};
}
 
//3
interface A{
   void m(){};
}
 
//4
interface A{
   default void m1(){};
   void m2();
}
 
//5
interface A{
   void m1();
   void m2();
}

Answers:

1.The given code prints:

i=1, j=0; i=2, j=0; i=2, j=1.

2. It will print

2, 1, 3.

3. It will throw j

ava.lang.IllegalArgumentException

. If one path has a root and the other does not, relativize cannot work, and it will throw an

IllegalArgumentException.

2, 5, 6, 7

lines will cause compilation failure.

4.

Summary