Can we overload a method in the same class where it is already defined?

  • No, method overloading is not allowed in Java.
  • Yes, by changing the access modifiers.
  • Yes, by changing the number or type of parameters.
  • Yes, by changing the return type.
In Java, you can overload a method in the same class by changing the number or type of parameters. Overloading based on the return type or access modifiers is not allowed. Method overloading is a technique where you have multiple methods in the same class with the same name but different parameter lists. This allows you to create methods with similar functionality but different inputs.

What does the >>> operator do in Java?

  • Bitwise OR operation
  • Left-shifts with sign extension
  • Logical AND operation
  • Right-shifts with zero fill
The >>> operator in Java is used for a logical right shift with zero fill. It shifts the bits of a binary number to the right and fills the leftmost bits with zeros. This operator is often used with bitwise operations to manipulate binary data. The other options do not accurately describe the >>> operator.

Which of the following methods does not close the file stream after appending the content to the file?

  • BufferedWriter's append method
  • FileWriter's append method
  • PrintWriter's append method
  • RandomAccessFile's writeBytes method
The BufferedWriter class in Java provides the append method for adding content to a file without closing the stream. This is useful when you want to continue writing to the same file later without reopening and closing it each time. The other options do not offer this behavior; they typically close the file stream after writing, making it less suitable for appending content.

If you are working on a highly concurrent system that uses many synchronized methods, and you notice that the application is facing performance issues, how might you optimize the application while maintaining thread safety?

  • Disable thread safety mechanisms to boost performance, relying on careful coding to prevent issues.
  • Implement custom synchronization mechanisms to fine-tune thread access to critical sections.
  • Increase the number of synchronized methods to reduce contention and improve performance.
  • Replace synchronized methods with java.util.concurrent classes and techniques like ConcurrentHashMap, ConcurrentLinkedQueue, and java.util.concurrent.locks.
In a highly concurrent system facing performance issues, it's better to replace synchronized methods with specialized classes and techniques from java.util.concurrent. These classes are designed to handle concurrency efficiently. Increasing synchronized methods may worsen contention. Disabling thread safety is not advisable, and implementing custom synchronization mechanisms can be error-prone and complex.

Arrays in Java are considered as ________ data types.

  • Primitive
  • Object
  • Immutable
  • Dynamic
Arrays in Java are considered as object data types. Even though they can store elements of primitive data types, arrays themselves are objects in Java. Understanding this distinction is essential for working with arrays and utilizing their various methods and properties.

What is the output of the following expression: 7 % 3?

  • 0
  • 1
  • 2
  • 3
In Java, the '%' operator is the modulo operator. It calculates the remainder when one number is divided by another. In this case, 7 divided by 3 equals 2 with a remainder of 1. So, the output of the expression 7 % 3 is 1.

How does Java's try-with-resources statement, introduced in Java 7, enhance exception handling?

  • It allows you to catch and handle exceptions thrown by resources automatically.
  • It allows you to catch multiple exceptions in one catch block.
  • It prevents the execution of the finally block.
  • It replaces the traditional try-catch block entirely.
Java's try-with-resources statement enhances exception handling by automatically closing resources (e.g., files, streams) after their scope, and if any exceptions are thrown during resource management, they are caught and handled automatically, simplifying resource cleanup.

What will be the output of the following code snippet: System.out.println("2" + "3");?

  • "23"
  • "5"
  • 5
  • Error
In the given code snippet, the + operator is used to concatenate two string literals: "2" and "3." Therefore, the output will be the concatenation of these two strings, which is "23." It's important to note that when the + operator is used with strings, it performs string concatenation, not arithmetic addition.

Consider a scenario where you want to evaluate multiple conditions and execute a block of code when at least one of the conditions is true. Which of the following control structures is the most appropriate?

  • do...while loop
  • for loop
  • if...else if ladder
  • while loop
In Java, when you need to evaluate multiple conditions and execute a block of code when at least one condition is true, the most appropriate control structure is the if...else if ladder. This structure allows you to test multiple conditions in sequence and execute the block associated with the first true condition. It's commonly used for handling multiple mutually exclusive cases.

The enhanced for loop (or for-each loop) is also known as the ________ loop.

  • Enhanced Loop
  • For Loop
  • For-Each Loop
  • Iteration Loop
The enhanced for loop in Java is often referred to as the "for-each" loop because it iterates through each element of an array or collection, making it a convenient way to loop through elements without explicitly defining an index. Options 1 to 3 are incorrect terms for describing this loop.