Basic and Advance Java Interview Questions & Answers Download PDF
Elevate your Java interview readiness with our detailed compilation of 81 questions. These questions will test your expertise and readiness for any Java interview scenario. Ideal for candidates of all levels, this collection is a must-have for your study plan. Secure the free PDF to access all 81 questions and guarantee your preparation for your Java interview. This guide is crucial for enhancing your readiness and self-assurance.
81 Java Questions and Answers:
Java Job Interview Questions Table of Contents:
1 :: What class allows you to read objects directly from a stream? briefly explain.?
The ObjectInputStream class supports the reading of objects from input streams.
2 :: Is Java a super set of JavaScript?
No. They are completely different. Some syntax may be similar.
3 :: What is the purpose of the enableEvents() method in Java Programming?
The enableEvents() method is used to enable an event for a particular object. Normally, an event is enabled when a listener is added to an object for a particular event. The enableEvents() method is used by objects that handle events by overriding their event-dispatch methods.
4 :: What is the Set interface in Java Programming?
The Set interface provides methods for accessing the elements of a finite mathematical set. Sets do not allow duplicate elements.
5 :: What an I/O filter in Java Programming?
An I/O filter is an object that reads from one stream and writes to another, usually altering the data in some way as it is passed from one stream to another.
6 :: How is it possible in Java Programming for two String objects with identical values not to be equal under the == operator?
The == operator compares two objects to determine if they are the same object in memory. It is possible for two String objects to have the same value, but located indifferent areas of memory.
7 :: How are this() and super() used with constructors in Java Programming?
this() is used to invoke a constructor of the same class. super() is used to invoke a superclass constructor in Java Programming.
8 :: What class allows you to read objects directly from a stream in Java Programming?
The ObjectInputStream class supports the reading of objects from input streams.
9 :: Name Container classes in Java Programming?
Container classes in Java:
Window,
Frame,
Dialog,
FileDialog,
Panel,
Applet,
or ScrollPane
Window,
Frame,
Dialog,
FileDialog,
Panel,
Applet,
or ScrollPane
10 :: What is casting in Java Programming?
There are two types of casting, casting between primitive numeric types and casting between object references. Casting between numeric types is used to convert larger values, such as double values, to smaller values, such as byte values. Casting between object references is used to refer to an object by a compatible class, interface, or array type reference.
11 :: What restrictions are placed on method overriding in Java Programming?
Overridden methods must have the same name, argument list, and return type. The overriding method may not limit the access of the method it overrides. The overriding method may not throw any exceptions that may not be thrown by the overridden method.
12 :: What restrictions are placed on method overloading in Java Programming?
Two methods may not have the same name and argument list but different return types.
13 :: How does multithreading take place on a computer with a single CPU in Java Programming?
The operating system’s task scheduler allocates execution time to multiple tasks. By quickly switching between executing tasks, it creates the impression that tasks execute sequentially.
14 :: What is the purpose of the File class in Java Programming?
The File class is used to create objects that provide access to the files and directories of a local file system.
15 :: What is the difference between the paint() and repaint() methods in Java Programming?
The paint() method supports painting via a Graphics object. The repaint() method is used to cause paint() to be invoked by the AWT painting thread.
16 :: What is the difference between static and non-static variables in Java Programming?
A static variable is associated with the class as a whole rather than with specific instances of a class. Non-static variables take on unique values with each object instance.
17 :: What are the problems faced by Java programmers who don’t use layout managers?
Without layout managers, Java programmers are faced with determining how their GUI will be displayed across multiple windowing systems and finding a common sizing and positioning that will work within the constraints imposed by each windowing system.
18 :: What advantage do Java’s layout managers provide over traditional windowing systems?
Java uses layout managers to lay out components in a consistent manner across all windowing platforms. Since Java’s layout managers aren’t tied to absolute sizing and positioning, they are able to accommodate platform-specific differences among windowing systems.
19 :: How are the elements of a GridBagLayout organized in Java Programming?
The elements of a GridBagLayout are organized according to a grid. However, the elements are of different sizes and may occupy more than one row or column of the grid. In addition, the rows and columns may have different sizes.
20 :: How can a GUI component handle its own events in Java Programming?
A component can handle its own events by implementing the required event-listener interface and adding itself as its own event listener.
21 :: Which class should you use to obtain design information about an object in Java Programming?
The Class class is used to obtain information about an object’s design.
22 :: Name primitive Java types?
The primitive types are byte, char, short, int, long, float, double, and boolean.
23 :: Does a class inherit the constructors of its superclass in Java Programming?
A class does not inherit constructors from any of its superclasses.
24 :: What is the Map interface in Java Programming?
The Map interface replaces the JDK 1.1 Dictionary class and is used associate keys with values.
25 :: If a class is declared without any access modifiers, where may the class be accessed in Java Programming?
A class that is declared without any access modifiers is said to have package or friendly access. This means that the class can only be accessed by other classes and interfaces that are defined within the same package.
