Unable to run Unix: lapdftext_unix_1_7_4-SNAPSHOT.tar.gz

[itegebo]

On Ubuntu 14.04 with several JVMs installed, I get the following while trying to run the scripts listed on this page:

java.lang.UnsupportedClassVersionError: edu/isi/bmkeg/lapdf/bin/ImagifySections : Unsupported major.minor version 51.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
    at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at com.exe4j.runtime.LauncherEngine.launch(Unknown Source)
    at com.install4j.runtime.launcher.Launcher.main(Unknown Source)

I've tried various approaches to overriding install4j's notion of the java home and what not. If I load the project into IntelliJ I can run the scripts. In reading the shell script apparently generated by install4j, it specifically selects for java 1.6 (see the test_jvm function), but the class files in the jar have been compiled with java 7:

javap -verbose edu.isi.bmkeg.lapdf.bin.ImagifySections|grep version
  minor version: 0
  major version: 51

I'm running Oracle's java.