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.class File Extension

File Type Java Class File

Developer Oracle
Category Developer files
File Format Binary

CLASS file type

A CLASS file is a compiled .JAVA file created by the Java compiler. It contains bytecode, which is binary program code that is executable when run by a Java Virtual Machine (JVM). CLASS files are commonly bundled into .JAR files, which are included in the $CLASSPATH environment variable for execution.

More Information

CLASS files can be compiled from JAVA files using the javac command, which is included with a JVM installation. Many Java IDEs, such as Eclipse, can compile CLASS files on the fly as developers write program code.

Since there are multiple versions of the JVM (e.g., 1.4, 1.5, and 1.6), some CLASS files may not be compatible with certain JVM versions. The Java Runtime Environment (JRE) can execute CLASS files, but it cannot compile them since it does not include the javac binary.

NOTE: Oracle acquired Sun Microsystems, the original developers of Java. The JRE and JVM are often used synonymously to refer to the platform that runs Java applications.

Programs that open CLASS files

Windows
Eclipse
dirtyJOE
DJ Java Decompiler
Oracle Java Virtual Machine
Linux
Eclipse IDE for Java Developers
Eclipse
Oracle Java Runtime Environment
JD-GUI
Oracle Java Virtual Machine
Macintosh
Eclipse
Apple Jar Launcher
Oracle Java Virtual Machine

About CLASS Files

Our goal is to explain what .class file is used for for and how to open it.

File Java Class File usage cases for Mac, Windows, Linux, Android, and iOS software listed on this page have been individually researched and verified using the FilesWiki team. We strive for 100% accuracy and only publish information about file formats that we have tested and verified.