java 13 interview questions and answers

All AWT event listeners extend the java.util.EventListener interface. In Core Java, AWT (Abstract Window Toolkit) event listeners typically extend interfaces provided by the java.awt.event package. The most commonly used interface for AWT event listeners is the ActionListener interface. So, the correct answer to your question would be: ActionListener interface is extended by AWT event listeners.

A compilation unit is a Java source code file. In the context of Core Java, a compilation unit refers to a source code file. It is the basic unit of compilation, typically containing a single Java class. A compilation unit can also include interface definitions, enumeration definitions, and annotation types. The Java compiler processes each … Read more

this is used to refer to the current object instance. super is used to refer to the variables and methods of the superclass of the current object instance. In Java, this and super are keywords used to refer to the current object and the parent class respectively. Here’s how they are used: this keyword: It refers to … Read more

An object must implement the Serializable or Externalizable interface before it can be written to a stream as an object. In Java, for an object to be written to a stream as an object, it must implement the Serializable interface. The Serializable interface is a marker interface, meaning it doesn’t declare any methods. Its purpose is to indicate to … Read more

The java.lang package is always imported by default. In Java, the java.lang package is always imported by default. This means that you don’t need to explicitly import classes from this package in your Java code; they are automatically available for use. Classes such as String, Object, and System are part of the java.lang package, and you can … Read more