Opening CLASS files

Have a problem opening a .CLASS file? We collect information about file formats and can explain what CLASS files are. Additionally we recommend software suitable for opening or converting such files.

What is the .CLASS file type?

A file containing the CLASS suffix represents a compiled form of a JAVA source file generated by Java compilers. A CLASS file usually has the same name as the related source file, for example will be transformed into Helloworld.class.

CLASS files contain a set of JAVA bytecode instructions like "Load and store" or "Object creation and manipulation". To facilitate storage and distribution of bulky applications, several .class files may be aggregated into a single .jar archive.

To run the required application, the bytecode gets verified and loaded into the Java Virtual Machine (JVM) which in turn either interprets it or compiles to machine code. Generally, interpretation results into much lower performance than compilation.

Class files are platform independent. It is also possible to build a .class file on one system and then execute it in a JVM on another system. However, since there are several modifications of CLASS files, some of them may be supported just by particular versions of the Java Virtual Machine.

Software to open or convert CLASS files

You can open CLASS files with the following programs:
Notepad++ by Notepad++ Team
DJ Java Decompiler
DJ Java Decompiler by Atanas Neshkov 2009

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