This problem exists when you upgrade from one version to another.because jdk is not automatically upgraded. For
For the same you can change the environmental varibles. In system variables look for the PATH and add the jdk bin location in the front of the string(not at the back);. onceOnce you have done that check in CMD if "java" and "javac" works. if it works, again go to system variables. add "CLASSPATH" A the variable and set value " .;c c:\Program Files\Java\jdk1.8.0_91\lib;"