ant build : unable to locate tools.jar. Expected find it in C:\Program Files\Java\jre7\lib\tools.jar

I too had this problem and solved it by setting variables like this :

[1] ANT_HOME - C:\apache-ant-1.9.3

[2] JAVA_HOME - C:\Program Files\Java\jdk1.7.0_21

[3] PATH - D:\Android_Development\android_sdk\platform-tools\;%ANT_HOME%\bin;%JAVA_HOME%\bin;D:\Android_Development\android_sdk\tools

Note : Set all these in System variables not in user variables.

This solved my problem.

Hope it helps.

To Recover this problems you can just copy the tools.jar from "C:\ProgramFiles\Java\jdk1.7.0\lib" directly into "C:\Program Files\Java\jre7\lib\".You will successfully recover the problems.

It works!..

I solved issue with setting %JAVA_HOME% to start of the PATH. It worked for me when I set it exactly to the start.