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Object Oriented Programming Articles
Page 585 of 588
When a thread is created and started, what is its initial state?
When a new thread begins its life cycle in the new state. It remains in this state until the program starts the thread. It is also referred to as a born thread.After this newly born thread is started, the thread becomes runnable. A thread in this state is considered to be executing its task.
Read MoreWhat is the difference between Object oriented programming and Object based programming?
Many of us have a misconception that Java script is an object oriented language. But, the truth is Java Script is an Object Based Language. Object Based languages are different from Object Oriented Languages: Object Based Languages Object based languages supports the usage of object and encapsulation. They does not support inheritance or, polymorphism or, both. Object based languages does not supports built-in objects. Javascript, VB are the examples of object bases languages. Object Oriented Languages Object Oriented Languages supports all the features of Oops including inheritance and polymorphism. They support built-in objects. C#, Java, VB. Net ...
Read MoreDifference between Java SE, Java EE, and Java ME?
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 MoreWhat is meant by Java being ‘write once run anywhere’ language?
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 MoreWhat is a JAR file?
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 MoreWhat is the difference between javac, java commands?
The javac command is used to compile Java programs, it takes .java file as input and produces bytecode. Following is the syntax of this command. >javac sample.java The java command is used to execute the bytecode of java. It takes byte code as input and runs it and produces the output. Following is the syntax of this command. >java sample Let us consider an example create a Sample Java program with name Sample.java Sample.java public class Sample { public static void main(String args[]) { System.out.println("Hi welcome ...
Read MoreWhat is meant by Java being an architecture neutral language?
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, Java compiler generates an architecture-neutral ...
Read MoreWhat does import Java.util.* in Java do?
Java util package contains collection framework, collection classes, classes related to date and time, event model, internationalization, and miscellaneous utility classes. On importing this package, you can access all these classes and methods.Following table lists out the classes in the collection package.InterfacesDescriptionClassesCollectionCollection Interface represents a group of objects. It is a root interface of collection framework.Abstract CollectionSetIt is a dynamic group of unique elements. It does not store duplicate element.HashSetLinkedHashSetListThey are similar to sets with the only difference that they allow duplicate values in them.StackvectorArrayListLinkedListQueueIt is an arrangement of the type First-In-First-Out (FIFO).First element put in the queue is the ...
Read MoreCan a method return multiple values in Java?
You can return only one value in Java. If needed you can return multiple values using array or an object. Example In the example given below the calculate() method accepts two integer variables performs the addition subtraction, multiplication and, division operations on them stores the results in an array and returns the array. public class ReturningMultipleValues { static int[] calculate(int a, int b){ int[] result = new int[4]; result[0] = a + b; result[1] = a - b; ...
Read MoreWhy the main method has to be in a java class?
Main method is the entry point of the execution in Java. When we execute a class JVM searches for the main method and execute the contents of it line by line. If you observe the following example you can compile a this program but if you try to execute it you will get an error saying “Main method not found”. Example abstract class SuperTest { public abstract void sample(); public abstract void demo(); } public class Example extends SuperTest{ public void sample(){ System.out.println("sample method ...
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