Java Generics Quiz – Java Generics Multiple Choice Questions and Answers

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Java Generics Quiz – Java Generics Multiple Choice Questions and Answers: Make use of this article and take part in the Java Generics Quiz. By giving a try for the Java Generics Online Quiz Test which you find on this page will help you know what kind of questions that are been asked in the technical interviews. As soon as you submit the Java Generics MCQ Quiz, you can get to know the Java Generics Multiple Choice Questions and Answers which will appear on the screen. So now, without any delay, give your try for the Java Generics Online Test and prepare for Java Generics concepts in the areas you are lagging.

Java Generics Quiz – Overview

Java Generics Online MCQ Quiz

What is the purpose of Java generics?
a) To provide type safety at compile-time
b) To provide type safety at runtime
c) To improve performance of Java code
d) To make Java code more readable
Answer: a) To provide type safety at compile-time
Explanation: Java generics allow for stronger type checking at compile-time, preventing potential type errors at runtime.

Which of the following is not a benefit of using Java generics?
a) Improved type safety
b) Code reuse
c) More efficient code execution
d) Better readability
Answer: c) More efficient code execution
Explanation: While generics may improve performance in some cases, this is not a primary benefit of using them. The main benefits are improved type safety, code reuse, and better readability.

What is a bounded type parameter in Java generics?
a) A type parameter with a specific upper bound
b) A type parameter with a specific lower bound
c) A type parameter with both an upper and lower bound
d) A type parameter without any bounds
Answer: a) A type parameter with a specific upper bound
Explanation: Bounded type parameters allow for greater flexibility in generic classes by restricting the type of object that can be passed in to a certain subset.

What is the syntax for defining a generic class in Java?
a) class MyClass
b) class MyClass
c) class T
d) class MyClass
Answer: b) class MyClass
Explanation: The type parameter is placed within angle brackets, immediately following the class name.

Which of the following is not a wildcard type in Java generics?
a) ?
b) *
c) +
d) –
Answer: d) –
Explanation: There is no wildcard type “-” in Java generics.

What is the difference between a bounded wildcard and an unbounded wildcard in Java generics?
a) A bounded wildcard has a specific upper or lower bound, while an unbounded wildcard has no bounds
b) A bounded wildcard has no bounds, while an unbounded wildcard has a specific upper or lower bound
c) A bounded wildcard can be used with multiple types, while an unbounded wildcard is limited to a single type
d) There is no difference between a bounded and unbounded wildcard
Answer: a) A bounded wildcard has a specific upper or lower bound, while an unbounded wildcard has no bounds
Explanation: Bounded wildcards are used to restrict the types that can be passed into a generic class or method, while unbounded wildcards have no such restrictions.

What is type erasure in Java generics?
a) The process of removing all generic type information during compilation
b) The process of adding generic type information during compilation
c) The process of enforcing generic type information at runtime
d) The process of dynamically updating generic type information during program execution
Answer: a) The process of removing all generic type information during compilation
Explanation: Type erasure is a feature of Java generics that allows for backward compatibility with non-generic Java code. During compilation, all generic type information is removed and replaced with non-generic code.

What is a raw type in Java generics?
a) A type with a specific upper or lower bound
b) A type with no bounds
c) A type with a specific upper bound
d) A type with a specific lower bound
Answer: b) A type with no bounds
Explanation: A raw type is a generic class or interface without any type parameters specified.

What is the purpose of the instanceof operator in Java generics?
a) To test whether an object is an instance of a specific class or interface
b) To test whether an object is an instance of a specific type
c) To test whether an object is of a specific generic type
d) To test whether an object is a subclass of a specific class or interface

Answer: a) To test whether an object is an instance of a specific class or interface
Explanation: The instanceof operator is used to test whether an object is an instance of a specific class or interface. It is not used to test for specific generic types.

What is the purpose of the extends keyword in a bounded type parameter?
a) To specify a lower bound for the type parameter
b) To specify an upper bound for the type parameter
c) To specify both an upper and lower bound for the type parameter
d) To specify a specific type for the type parameter
Answer: b) To specify an upper bound for the type parameter
Explanation: The extends keyword is used in a bounded type parameter to specify an upper bound for the type. This restricts the type to a specific subset of possible types.

What is the purpose of the super keyword in a bounded type parameter?
a) To specify a lower bound for the type parameter
b) To specify an upper bound for the type parameter
c) To specify both an upper and lower bound for the type parameter
d) To specify a specific type for the type parameter
Answer: a) To specify a lower bound for the type parameter
Explanation: The super keyword is used in a bounded type parameter to specify a lower bound for the type. This restricts the type to a specific subset of possible types.

Which of the following statements about type inference in Java generics is true?
a) Type inference is not supported in Java generics
b) Type inference is supported only for method calls, not for variable declarations
c) Type inference is supported for both method calls and variable declarations
d) Type inference can be used to infer both the upper and lower bounds of a type parameter
Answer: c) Type inference is supported for both method calls and variable declarations
Explanation: Type inference allows the Java compiler to infer the type arguments of a generic method or constructor call. It can also be used for variable declarations with the diamond operator (<>).

What is the purpose of the diamond operator in Java generics?
a) To specify a lower bound for a type parameter
b) To specify an upper bound for a type parameter
c) To specify both an upper and lower bound for a type parameter
d) To allow for type inference in a generic class or method
Answer: d) To allow for type inference in a generic class or method
Explanation: The diamond operator (<>), when used in a generic class or method, allows for type inference by telling the compiler to infer the type argument(s) from the context.

What is the difference between a raw type and a parameterized type in Java generics?
a) A raw type has type parameters specified, while a parameterized type does not
b) A raw type has no type parameters specified, while a parameterized type does
c) A raw type can be used with any type, while a parameterized type is limited to a specific type
d) There is no difference between a raw type and a parameterized type
Answer: b) A raw type has no type parameters specified, while a parameterized type does
Explanation: A raw type is a generic class or interface without any type parameters specified, while a parameterized type is a generic class or interface with type parameters specified.

Which of the following statements about type erasure in Java generics is true?
a) Type erasure is a runtime feature of Java generics
b) Type erasure is a compile-time feature of Java generics
c) Type erasure allows for stronger type checking at runtime
d Type erasure is a runtime feature of Java generics
Answer: b) Type erasure is a compile-time feature of Java generics
Explanation: Type erasure is the process by which the Java compiler replaces generic types with their non-generic counterparts. This happens at compile time, and the resulting code does not contain any information about generic types.

Which of the following statements about wildcard types in Java generics is true?
a) Wildcard types can be used to specify an upper bound for a type parameter
b) Wildcard types can be used to specify a lower bound for a type parameter
c) Wildcard types can be used to represent an unknown type
d) Wildcard types can be used to specify a specific type for a type parameter
Answer: c) Wildcard types can be used to represent an unknown type
Explanation: Wildcard types in Java generics are used to represent an unknown type. They are denoted by the “?” symbol and can be used in situations where the specific type of a generic parameter is not important.

Which of the following statements about type bounds in Java generics is true?
a) A type parameter can have both an upper and lower bound
b) A type parameter can have only an upper bound
c) A type parameter can have only a lower bound
d) Type bounds are not supported in Java generics
Answer: a) A type parameter can have both an upper and lower bound
Explanation: A type parameter in Java generics can have both an upper and lower bound, which is specified using the syntax “T extends Bound1 & Bound2”. This restricts the type parameter to a specific subset of possible types.

What is the purpose of the @SuppressWarnings annotation in Java generics?
a) To suppress compiler warnings related to unchecked conversions
b) To suppress runtime warnings related to unchecked conversions
c) To indicate that a method or class should not be used in production code
d) To indicate that a method or class is experimental and subject to change
Answer: a) To suppress compiler warnings related to unchecked conversions
Explanation: The @SuppressWarnings annotation in Java generics is used to suppress compiler warnings related to unchecked conversions. It can be applied to a method, class, or variable declaration.