ANT 1.8.2 fresh install NoClassDefFoundError

Question

I'm trying to configure ant 1.8.2 on my windows 10 machine and I'm getting the following error:

java.lang.NoClassDefFoundError
        at org.apache.tools.ant.launch.Locator.class$(Locator.java:134)
        at org.apache.tools.ant.launch.Locator.getResourceSource(Locator.java:134)
        at org.apache.tools.ant.launch.Locator.getClassSource(Locator.java:118)
        at org.apache.tools.ant.launch.Launcher.run(Launcher.java:175)
        at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)
Caused by: java.lang.ClassNotFoundException: org/apache/tools/ant/launch/Locator
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:195)
        ... 5 more

Environment variables are configured as expected:

JAVA_HOME = C:\Program Files\Java\jdk1.7.0_80

ANT_HOME = C:\apache-ant-1.8.2

Both variables are included on PATH with \bin.

The ant command throws the exception as well as running ANT with the absolute path.

I have already unzipped it several times but honestly I'm running out of ideas.

Problem resolved: After a lot of struggle the problem was actually inside the JDK. Reinstalling it as administrator resolved the issue.