A few days ago I was setting my development environment up and it involved executing some Apache Ant tasks. I had installed latest Java 7, jdk1.7.0_80 to be exact and Ant 1.8.4, required by the project.

Attempted to compile it and got this output:

The first line logged by Apache Ant hints tools.jar is missing. The most common cause for this error is to have forgotten to install Java Development Kit (JDK) and/or have JAVA_HOME pointing to an actual Java Runtime Environment (JRE) installation instead of a JDK one, JRE doesn’t ship with tools.jar, but as it can be observed, the last line of previous output states JAVA_HOME is set to "C:\Program Files\Java\jdk1.7.0_80".

The problem seems to be that JDK 1.7.0_80 removed tools.jar from JAVA_HOME/lib, the solution to this issue was to install JDK 1.7.0_76 and update JAVA_HOME accordingly.