How to run java class file

How do I run a Java class?

How to run a java program

  1. Open a command prompt window and go to the directory where you saved the java program (MyFirstJavaProgram. java). …
  2. Type ‘javac MyFirstJavaProgram. java’ and press enter to compile your code. …
  3. Now, type ‘ java MyFirstJavaProgram ‘ to run your program.
  4. You will be able to see the result printed on the window.

How do I get a .java file from a .class file?

In order to decompile class file, just open any of your Java projects and go to Maven dependencies of libraries to see the jar files included in your project. Just expand any jar file for which you don’t have the source attached in Eclipse and click on the . class file.

How do you run a Java program in multiple classes?

Run by typing java classname. For example, java smtpClient. Note: If you are using multiple classes in your program you will need to compile all of the files and then run the program by using the classname of the class that contains your main method. You should see the output.

How do I run a Java program in another directory?

Following are the steps to run java class file which is in different directory:

  1. Step 1 (Create utility class): Create A. …
  2. Step 2 (Compile utility class): Open terminal at proj1 location and execute following commands. …
  3. Step 3 (Check whether A. …
  4. Step 4 (Write main class and compile it): Move to your proj2 directory.

7 мая 2019 г.

How do I install Java?

Install Java

  1. Goto and click on the Free Java Download button.
  2. Click on the Save button and save Java software on the Desktop.
  3. Verify that Java software is saved on the Desktop.
  4. Open Windows Command Prompt window. …
  5. cd <Java download directory>
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How run Java jar from command line?

From command prompt

Open a command prompt and cd into your project folder. Then run the java command with these arguments: java -cp bin:lib/parserlib. jar:lib/physics.

Can we decompile Java class file?

The tool that I prefer is “Java Decompiler” which can be found at In this tool, I prefer Java Decompiler’s UI version which is known as “JD-GUI”. JD-GUI is a standalone application that is used to display Java source codes of . class files.

Can Java be decompiled?

Java source code is compiled to a class file that contains byte code. … The problem is that the class file can easily be decompiled into the original source code using Java decompiler tools. The best solution to prevent reverse-engineering is to obfuscate the class file so that is will be very hard to reverse-engineer.

How do I run a .jar file?

jar, follow these rules:

  1. Open a notepad.exe.
  2. Write : java -jar Example. jar.
  3. Save it with the extension . bat.
  4. Copy it to the directory which has the . jar file.
  5. Double click it to run your . jar file.

Can I have multiple classes in one Java file?

In Java, you can define multiple top level classes in a single file, providing that at most one of these is public (see JLS §7.6).

How do I compile multiple Java files?

How to compile multiple source files by name:

  1. Open a shell on the machine you wish to compile on.
  2. Change directory (cd) to the directory that contains the source file(s) (. java) that you want to compile.
  3. Enter the following command (modifying the source names as appropriate)
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How can I run multiple Java files in NetBeans?

5 Answers

  1. Open a new project with a specific name (File -> New project and complete the walk-thru) in NetBeans.
  2. You can create any number of new classes under one project by going to File -> New File -> and completing the walk-thru. …
  3. Create yet another file (by going thru File -> New File etc.).

4 мая 2014 г.

How do you call another file in Java?

2 Answers

  1. Make the method of B class public (or public static)
  2. Create a object of B class in A (or if method is static this step is not required)
  3. Using that object(in case of static user class name) call the method.

How do you set classpath?


  1. Select Start, select Control Panel. double click System, and select the Advanced tab.
  2. Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. …
  3. In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK.

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