mshuler@hana:~$ vi KeyLengthDetector.java
mshuler@hana:~$ javac KeyLengthDetector.java 
mshuler@hana:~$ ls KeyLengthDetector.
KeyLengthDetector.class  KeyLengthDetector.java   
mshuler@hana:~$ java KeyLengthDetector 
The allowed key length for AES is: 2147483647
mshuler@hana:~$ java -version
java version "1.8.0_121"
Java(TM) SE Runtime Environment (build 1.8.0_121-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)
mshuler@hana:~$ sudo update-java-alternatives --list
java-1.6.0-openjdk-amd64 1061 /usr/lib/jvm/java-1.6.0-openjdk-amd64
java-1.7.0-openjdk-amd64 1071 /usr/lib/jvm/java-1.7.0-openjdk-amd64
java-1.8.0-openjdk-amd64 1069 /usr/lib/jvm/java-1.8.0-openjdk-amd64
java-7-oracle 73 /usr/lib/jvm/java-7-oracle
java-8-oracle 83 /usr/lib/jvm/java-8-oracle
mshuler@hana:~$ sudo update-java-alternatives --set java-1.8.0-openjdk-amd64
update-java-alternatives: plugin alternative does not exist: /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so
mshuler@hana:~$ rm KeyLengthDetector.class
mshuler@hana:~$ java -version
openjdk version "1.8.0_121"
OpenJDK Runtime Environment (build 1.8.0_121-8u121-b13-1~bpo8+1-b13)
OpenJDK 64-Bit Server VM (build 25.121-b13, mixed mode)
mshuler@hana:~$ javac -version
javac 1.7.0_121
mshuler@hana:~$ javac KeyLengthDetector.java 
mshuler@hana:~$ java KeyLengthDetector 
The allowed key length for AES is: 2147483647
mshuler@hana:~$