Java Articles - Page 743 of 745

A java archive file is a file format/ archiving tool which contains all the components of an executable Java application. All the predefined libraries are available in this format. To include any of these (other than rt.jar) in to your project you need to set the class path for this particular JAR file. You can create a JAR file using the command line options or using any IDE’s. Creating a Jar file You can create a Jar file using the jar command as shown below. jar cf jar-file input-file(s) Let us consider an example, create a Sample Java ... Read More

Unlike many other programming languages including C and C++, when Java is compiled, it is not compiled into platform specific machine, rather into platform independent byte code. This byte code is distributed over the web and interpreted by the Virtual Machine (JVM) on whichever platform it is being run on. Thus when you write a piece of Java code in a particular platform and generated an executable code .class file. You can execute/run this class file on any system the only condition is that the target system should have JVM (JRE) installed in it. In Short, If you have a ... Read More

The final modifier for finalizing the implementations of classes, methods, and variables. The main purpose of using a class being declared as final is to prevent the class from being subclassed. If a class is marked as final then no class can inherit any feature from the final class. You cannot extend a final class. If you try it gives you a compile time error. Example final class Super { private int data = 30; } public class Sub extends Super{ public static void main(String args[]){ } } Output ... Read More

When you compile Java programs using javac compiler it generates bytecode. We need to execute this bytecode using JVM (Java Virtual machine) Then, JVM translates the Java bytecode to machine understandable code.You can download JVM’s (comes along with JDK or JRE) suitable to your operating system and, once you write a Java program you can run it on any system using JVM.

Java uses javac (compiler) to convert the java code to byte code (.class file).Then, JVM internally converts the bytecode to system understandable code using an interpreter in addition to it JVM.Instead of executing a piece of code, again and again, JVM identifies them as “hot spots” and compiles them using Just in time compiler and, later reuses the same when required.

Java provides three editions JSE, JEE, JME. JSE − Java Standard Edition using this, you can develop stand-alone applications. This provides the following packages − java.lang − This package provides the language basics. java.util − This package provides classes and interfaces (API’s) related to collection framework, events, data structure and other utility classes such as date. java.io − This package provides classes and interfaces for file operations, and other input and output operations. java.math − This package provides classes and interfaces for multiprecision arithmetics. java.nio − This package provides classes and interfaces the Non-blocking I/O framework for Java java.net ... Read More

You can find the version of the Java software currently installed in your system using Programs and using Command prompt. Using Command prompt The -version command of the java command prompt gives you the current version of the Java software installed in your system. Therefore, open command prompt and type the command java -version to get the version of Java installed in your system. Using the Java program The System class of java.lang package provides a method named getProperty() this method accepts one of the following string parameters an returns the respective property. To get the version of the ... Read More

The System class of java.lang package provides a method named getProperty() this method accepts one of the following string parameters an returns the respective property. java.class.path − If you pass this value as a parameter, the getProperty() method returns the current classpath. java.home − If you pass this value as a parameter, the getProperty() method returns the current Installation directory of the JRE. java.vendor − If you pass this value as a parameter, the getProperty() method returns the current vendor name of the JRE. java.vendor.url − If you pass this value as a parameter, the getProperty() method returns the ... Read More

IntelliJ and NetBeans are the alternative IDE’s for Java development.

In fact, you can directly start learning Java without any prior knowledge of programming language. But, the syntax in Java is similar to the syntax of the C programming language, therefore, Knowing C language helps to get hold of Java quickly. Having introduced to object-oriented principles before starting Java, also helps in the understanding of the language so, having an idea on object-oriented languages such as C++ also helps. In short, if you know C or C++ it will be a little bit easier to cope with Java technology.