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Java Basics

1/25 What is the purpose of the 'finalize' method in Java?
- To initialize variables
- To clean up resources before an object is garbage collected
- To finalize a class definition
- To finalize variable assignments
2/25 What is the primary purpose of the 'super' keyword in Java?
- To call a method of the parent class
- To declare variables
- To create a new instance of the parent class
- To override a method in the child class
3/25 Which of these is not a valid Java access modifier?
- public
- protected
- private
- friend
4/25 Which method is called when an object is cloned in Java?
- cloneMethod()
- copy()
- clone()
- Object.clone()
5/25 What is the purpose of the 'this' keyword in Java?
- To refer to the current class instance variable
- To create a new instance of a class
- To terminate the current method
- To invoke a method of the superclass
6/25 What does the 'static' keyword in Java signify?
- The method can be called without creating an instance of the class
- The method is immutable
- The method is synchronized
- The method returns a static value
7/25 In Java, what does the 'volatile' keyword do to a variable?
- It ensures the variable is synchronized across threads
- It makes the variable immutable
- It increases the variable's access speed
- It makes the variable transient
8/25 Which of the following is true about a 'final' class in Java?
- It can be extended by other classes
- It cannot be instantiated
- It can have final methods only
- It cannot be extended by other classes
9/25 What is the significance of the 'main' method in a Java application?
- It's the method that runs when a class is instantiated
- It's used to define variables
- It's the entry point of a Java application
- It's used to clean up resources before exiting the application
10/25 Which of these data types is used to represent a single character in Java?
- String
- char
- Character
- byte
11/25 How do you handle exceptions in Java?
- Using try-catch blocks
- By using the 'throws' keyword
- By using the 'extends' keyword
- By declaring them as static
12/25 In Java, what is the difference between '==' and 'equals()'?
- '==' checks for value equality, 'equals()' checks for reference equality
- '==' checks for reference equality, 'equals()' checks for value equality
- There is no difference
- 'equals()' is used only for strings
13/25 What is the purpose of the 'package' statement in Java?
- To enhance the performance of the application
- To create a new thread
- To define a namespace for classes
- To import external libraries
14/25 What is 'autoboxing' in Java?
- Automatically converting a primitive type into its corresponding wrapper class
- The process of optimizing code automatically
- Creating an automatic backup of the code
- A feature for automatic memory management
15/25 Which method must be implemented in a class that implements the java.util.Comparator interface?
- compare()
- compareTo()
- equals()
- hashCode()
16/25 How do you declare a constant variable in Java?
- Using the 'constant' keyword
- Using the 'static final' keywords
- Using the 'immutable' keyword
- Declaring without initialization
17/25 In Java, what is the purpose of the Collections.sort() method?
- To sort elements of a collection in descending order
- To randomly shuffle elements of a collection
- To sort elements of a collection in ascending order
- To reverse the order of elements in a collection
18/25 In Java, which method you must override to use an object as a key in a HashMap?
- hashKey()
- mapKey()
- equals() and hashCode()
- getKey()
19/25 What is the purpose of the 'volatile' keyword in Java?
- To make a variable thread-safe by ensuring atomic access to it
- To optimize the code during compilation
- To indicate that a variable's value will not change
- To store the variable value permanently in the database
20/25 What is the difference between 'static' and 'non-static' methods in Java?
- Static methods can be called without creating an instance of the class
- Non-static methods are always synchronized
- Static methods are faster
- Non-static methods can access any class variable
21/25 In Java, what does the 'transient' keyword do when applied to a class field?
- Makes the field non-serializable
- Marks the field as temporary and not part of the class's persistent state
- Indicates that the field value can change rapidly
- Makes the field volatile
22/25 In Java, what is the purpose of the 'enum' keyword?
- To define a new exception type
- To declare a collection of constants
- To create an enumeration of values for iteration
- To optimize memory usage in large applications
23/25 What does the 'this' keyword refer to in Java?
- The current method
- The current instance of the class in which it is used
- A static context in the class
- The superclass of the current class
24/25 What does the 'static' keyword signify when applied to a block of code in Java?
- The code block is related to the static members of the class
- The code block cannot be modified
- The code block is executed when the JVM loads the class
- The code block is executed immediately after the class is instantiated
25/25 What is 'type casting' in Java?
- Changing a variable from one type to another
- A method of error handling
- A process of making a class adhere to a specific interface
- Assigning a new value to a variable
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