When you have both java6 and java7 installed, the default java may not be java 7.
Do this by typing java -version, and check the output.
- If the output is like "java version "1.7.0_xx", then the default java is java 7, which is good.
- If the output is like "java version "1.6.0_xx", then the default java is java 6, we need to configure default java to java 7.
If the default java is java 6, then do
On Debian/Ubuntu:
sudo update-alternatives --config java
On CentOS/RHEL:
sudo alternatives --config java
The above command will ask you to choose one of the installed java as the default. You should choose java 7 here.
After that, you should re-run java -version to make sure the change has taken effect.