What is a .Class File?
A .class file is a compiled Java class file. It is a binary file containing Java bytecode that can be executed on the Java Virtual Machine (JVM). These files are usually generated by the Java compiler from .java source files.
How to Open a .Class File?
A .class file cannot be opened directly and must be executed through the Java Runtime Environment (JRE). You can open a .class file by running it with the Java command-line tool. The syntax is:
java <CLASS FILE>
Where <CLASS FILE> is the name of the .class file you want to run.
For example, if you have a file named HelloWorld.class, you can run it with the following command:
java HelloWorld
If the .class file is in a different directory, you can specify the full path to it:
java /path/to/HelloWorld.class
Alternatively, you can use the javaw command to open a .class file. The syntax is:
javaw <CLASS FILE>
Where <CLASS FILE> is the name of the .class file you want to run.
For example, if you have a file named HelloWorld.class, you can run it with the following command:
javaw HelloWorld
If the .class file is in a different directory, you can specify the full path to it:
javaw /path/to/HelloWorld.class
It is also possible to open a .class file with a Java IDE, such as IntelliJ IDEA, Eclipse, or NetBeans. All these IDEs provide an easy way to run a .class file.
Conclusion
A .class file is a compiled Java class file containing Java bytecode that can be executed on the Java Virtual Machine (JVM). You can open a .class file by running it with the Java command-line tool or the javaw command, or by using a Java IDE.