CODEBURST : JAVA EDITION

Which of the following correctly overrides the `equals` method of the `Object` class?

• public boolean equals(Object obj)
• public void equals(Object obj)
• private boolean equals(Object obj)
• public boolean equals(MyClass obj)

Which exception is thrown when a thread is waiting, sleeping, or occupied and the thread is interrupted?

• InterruptedException
• IllegalThreadStateException
• IOException
• TimeoutException

What is the output of the following code?

String str = null;

System.out.println(str + "abc");

• nullabc
• abc
• Compile time error
• NullPointerException

What is the result of compiling and running this code?

int x = 5;

System.out.println(x++ + ++x);

• 11
• 12
• 10
• 13

Which of the following is used to restrict a class from being subclassed?

• static
• abstract
• final
• protected

Which method must be implemented when a class implements the `Runnable` interface?

• start()
• run()
• execute()
• init()

Which keyword is used to prevent method overriding?

• final
• static
• private
• abstract

Which of the following statements is true about Java's garbage collection?

• You can directly invoke garbage collection.
• Java uses reference counting for garbage collection.
• The finalize() method is guaranteed to be called.
• Objects without references are eligible for GC.

Which of these is not a functional interface in Java 8?

• Predicate
• Comparator
• Runnable
• String

Which class is used to create an unmodifiable list in Java?

• Collections.unmodifiableList()
• List.unmodifiable()
• Arrays.asList()
• List.of()