Source: javaindos.
Let’s say your file is in C:\mywork\
Run Command Prompt
C:\> cd \myworkThis makes C:\mywork the current directory.
C:\mywork> dirThis displays the directory contents. You should see
filenamehere.java among the files.C:\mywork> set path=%path%;C:\Program Files\Java\jdk1.5.0_09\binThis tells the system where to find JDK programs.
C:\mywork> javac filenamehere.javaThis runs javac.exe, the compiler. You should see nothing but the
next system prompt…C:\mywork> dirjavac has created the filenamehere.class file. You should see
filenamehere.java and filenamehere.class among the files.C:\mywork> java filenamehereThis runs the Java interpreter. You should then see your program
output.If the system cannot find javac, check the set path command. If javac
runs but you get errors, check your Java text. If the program
compiles but you get an exception, check the spelling and
capitalization in the file name and the class name and the java
HelloWorld command. Java is case-sensitive!