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Java Basics

1/25 What is the effect of marking a method as 'synchronized' in Java?
- It makes the method run faster
- It allows multiple threads to access the method simultaneously
- It ensures only one thread can access the method at a time
- It makes the method available to all classes
2/25 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
3/25 What is the default size of a 'HashSet' in Java?
- 16
- 10
- 12
- 32
4/25 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
5/25 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
6/25 Which of these is an immutable class in Java?
- java.lang.StringBuilder
- java.lang.String
- java.lang.StringBuffer
- java.util.ArrayList
7/25 In Java, what is the default layout manager for a JPanel?
- FlowLayout
- BorderLayout
- GridLayout
- CardLayout
8/25 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
9/25 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
10/25 Which of the following is a checked exception in Java?
- NullPointerException
- ArrayIndexOutOfBoundsException
- IOException
- RuntimeException
11/25 Which Java feature allows runtime binding of method calls?
- Static Typing
- Dynamic Binding
- Method Overloading
- Method Overriding
12/25 Which method is used to compare two strings for equality in Java?
- compareTo()
- equals()
- equalsIgnoreCase()
- compare()
13/25 In Java, which method you must override to use an object as a key in a HashMap?
- hashKey()
- mapKey()
- equals() and hashCode()
- getKey()
14/25 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
15/25 In Java, what is 'reflection' used for?
- To modify the behavior of a program at runtime
- To duplicate objects
- To analyze the performance of applications
- To convert primitive types into objects
16/25 What is the purpose of a 'constructor' in Java?
- To create and initialize an object
- To destroy an object
- To declare variables
- To return the value of an object
17/25 In Java, what is the default layout manager for the JFrame container?
- FlowLayout
- GridLayout
- BorderLayout
- CardLayout
18/25 What is the use of the 'implements' keyword in Java?
- To inherit from an abstract class
- To include an interface in a class
- To mark a method as mandatory to override
- To declare a class as abstract
19/25 What is the primary purpose of the 'try-with-resources' statement in Java?
- To execute a block of code multiple times
- To automatically close resources after execution
- To handle multiple exceptions in a single catch block
- To improve the performance of try-catch blocks
20/25 What is 'polymorphism' in the context of Java?
- The ability of a variable to hold objects of different types
- The ability of Java to run on different platforms without modification
- The ability of a method to perform different tasks based on the object
- Changing the behavior of an object at runtime
21/25 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
22/25 In Java, which method would you use to compare two String objects for content equality?
- compareTo()
- equals()
- match()
- equalContent()
23/25 What is the use of the 'protected' access modifier in Java?
- To restrict access to the class members within its own class only
- To provide access to the class members within the same package and subclasses
- To provide universal access from any other class
- To prevent modification of the class members
24/25 What is the advantage of using a 'PreparedStatement' in JDBC?
- Faster execution for repeated queries
- Allows execution of dynamic queries only
- Automatically closes database connections
- Improves the UI of the application
25/25 In Java, what is 'exception chaining'?
- Linking multiple exceptions together
- Creating a chain of methods that can throw exceptions
- Catching multiple exceptions in one catch block
- Calling a method that throws an exception from another that also throws an exception
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