B4J Question install jdk 8 u101 on RPI 2

[suciwulans]

for the first time
download jdk-8u101-linux-arm-vfp-hflt.tar.gz for Linux ARM v6/v7 Hard Float ABI.

2. $ sudo tar zxvf jdk-8u101-linux-arm-vfp-hflt.tar.gz -C /opt

3. $ sudo update-alternatives --install /usr/bin/javac javac /opt/jdk1.8.0_101/bin/javac 1
4. $ sudo update-alternatives --install /usr/bin/java java /opt/jdk1.8.0_101/bin/java 1
5. $ sudo update-alternatives --config javac
6. $ sudo update-alternatives --config java

7. $ java -version
8. $ javac -version
when i running my program using java -jar gps.jar always full screen? why?
i use UI application with internal designer.