a. classpath
.;C:/Program Files/Java/jdk1.7.0_21/lib/tools.jar;C:/Program Files/Java/jdk1.7.0_21/lib/dt.jar;
b. JAVA_HOME
C:/Program Files/Java/jdk1.7.0_21
c. path
%JAVA_HOME%/bin;%JAVA_HOME%/lib/dt.jar;%JAVA_HOME%/jre/bin;%CATALINA_HOME%/lib;%CATALINA_HOME%/lib/servlet-api.jar;%CATALINA_HOME%/lib/jsp-api.jar