Jenkins installs Java twice if latest jdk is specified from tools configuration.

first, jdk1.8.0_121 will be installed if no java present on target slave and it may be checked from http://<jenkins>/computer/<slave>/log.

second, jdk1.8.0_144 will be installed on slave, it may be checked from http://<jenkins>/job/<jobname>/<buildnum>/console

but only jdk1.8.0_144 is specified for installation in http://<jenkins>/configureTools/

I think it's a bug, because it doubles network traffic on massive slave creation.

for example, if 100 slaves should be created - it will be 175M * 100 unnecessarily downloaded data. we may create/destroy up to 1000 slaves per day, so it's a bug for us