Found 33676 Articles for Programming

How to create a JAR file?

usharani
Updated on 24-Feb-2020 09:39:53

24K+ Views

You can create a JAR file using the following command.jar cf jar-file input-file(s)  You can also create JAR files using IDE’s. To create a JAR file using eclipse follow the procedure given below.Open the Jar File wizardThe Jar File wizard can be used to export the content of a project into a jar file. To bring up the Jar File wizard −In the Package Explorer select the items that you want to export. If you want to export all the classes and resources in the project just select the project.Click on the File menu and select Export.In the filter text box ... Read More

What is a JAR file?

varun
Updated on 30-Jul-2019 22:30:20

3K+ Views

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

What is meant by Java being ‘write once run anywhere’ language?

seetha
Updated on 30-Jul-2019 22:30:20

388 Views

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

What are final classes in Java?

Sreemaha
Updated on 30-Jul-2019 22:30:20

11K+ Views

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

What is meant by Java being platform-independent?

vanithasree
Updated on 30-Jul-2019 22:30:20

373 Views

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.

How to close all the opened files using Python?

Rajendra Dharmkar
Updated on 17-Jul-2023 13:18:54

6K+ Views

In Python, file-handling tasks like opening, reading, writing, and closing files, or manipulating data in files are a common occurrence. While opening files has its significance and utility, it's equally important that files are closed properly to release system resources and to ensure that data integrity is maintained. In this article, we will explore different methods and techniques to close multiple opened files in Python, permitting you to optimize your file-handling operations and maintain clean code. Making Use of a Context Manager In Python, context managers are a tool for efficiently managing resources that need to be properly ... Read More

What is just-in-time or JIT compiler and what does it do?

radhakrishna
Updated on 30-Jul-2019 22:30:20

350 Views

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.

Difference between Java SE, Java EE, and Java ME?

mkotla
Updated on 30-Jul-2019 22:30:20

2K+ Views

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

How to change the root directory of the current process in Python?

Rajendra Dharmkar
Updated on 03-Oct-2019 06:21:11

1K+ Views

You can use the os.chroot to change the root directory of the current process to path. This command is only available on Unix systems. You can use it as follows:>>> import os >>> os.chroot('/tmp/my_folder')This changes the root directory of the script running to /tmp/my_folder.

How to change the user and group permissions for a directory using Python?

Rajendra Dharmkar
Updated on 13-Dec-2019 07:14:14

607 Views

You can change the owner of a file or a directory using the pwd, grp and os modules. The uid module is used to get the uid from user name, grp to get gid group name string and os to change the owner:Exampleimport pwd import grp import os uid = pwd.getpwnam("my_name").pw_uid gid = grp.getgrnam("my_group").gr_gid path = 'my_folder' os.chown(path, uid, gid)

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