Usually solving problems with CLASS file is simple – just install proper software and open the file. Read the guide and open CLASS file now!
The Java CLASS file format is a platform-independent binary file used to store compiled Java code. CLASS files contain bytes that can represent Java byte code, referenced classes and other data that pertain to the structure of the compiled program.
CLASS files may be compiled using the javac command from the command line. When executed, the Java Virtual Machine reads the CLASS file and translates it into a sequence of Bytecode instructions which are then used to generate output. CLASS files can be opened in any text-editor, although this will give little useful information due to them being binary files.
There could be multiple reasons for which the system does not support given file. In the case of CLASS extension, it is probable that none of the installed programs support given file type. Therefore, user should undertake the following steps
If an application that supports CLASS files is installed on user’s system, but is not used to open such files by default, right-click on the file icon and choose "Open with" option from the menu. Next, select the proper application and check the "Always use the selected application to open this kind of files" box. The system will store this information in its registry and use the selected program to open files with CLASS extension by default.
For Mac OS users the procedure is analogous – open the file menu by right-clicking on the CLASS file and choose "Information" option and select "Open with program" option. From the submenu select an application and click on "Change all" button.
Inability to open CLASS files may also be related to the lack of any application that supports given file being installed on the system. Should that be the case, user needs to download and install one of the following applications. Once installed, the system will automatically associate newly installed application with CLASS files. If this step fails, see step 1.
Sometimes, although relatively rarely, steps 1 and 2 might not lead to expected results. There can be several reasons for such situation to occur: