I am using JDK 1.5 version on my machine, installed JRE is of java 1.5, using ant build.xml file
and Need to use java 1.6 to compile some files using the same ant build.xml (via ant build method)
I have not installed java 1.6 jre on my machine but just have a copied folder which has JDK 1.6.0_25, can we specify the java compiler and the jar files related to 1.6 , so that the files
can be compiled using java 1.6
Yes you should be able to. Carefully read the javac task docs (http://ant.apache.org/manual/Tasks/javac.html), paying attention to the fork (set it to "yes") and executable (set it to the javac.exe within the java1.6.0_25/bin directory) properties.