Java 1.0 Physlets
Go to the archive for each Physlet and look for the documentation/download link. Java 1.0 Physlets are usually distributed as ZIP archives that must be decompressed using a standard utility program such as WinZIP. The class files for each Physlets are in directories within the archive.
Java code is compiled into an intermediate state called a class file. These class files contain the byte code for the Java virtual machine and have the "class" file extension. A typical programming project may produce dozens of class files. Since most Java programmers organize their projects into packages, there will often be a number of subdirectories each containing one or more class files, as sown in figure 8. When using an applet, you may copy the entire file structure containing an applet's class files and all the associated subdirectories to a new location on a hard disk, but you must not change the names of any files or subdirectories. Since Java has its roots in Unix, even capitalization is important!
Note: Java 1.0 Physlets are not being actively supported.
Please use a Java 1.1 Physlet whenever possible.