Java error when trying to run UBCG jar (java.lang.ClassNotFoundException)

Question

I wanna install UBCG.JAR in ubuntu 18.04 but I cannot run the java File UBCG.JAR.
when I type the code java -jar UBCG.JAR an error message appears.

Exception in thread "main" java.lang.NoClassDefFoundError: org/json/simple/parser/ParseException
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:398)
at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:56)

Caused by: java.lang.ClassNotFoundException: org.json.simple.parser.ParseException
    at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    ... 3 more

Fabio · Answer

I solved this problem but UBCG.JAR does not work with java 11 . It is necessary to install openjdk-8-jre and switch the default java.
Install openjdk-8-jre
$ sudo apt-cache policy openjdk-8-jre
$ sudo apt install openjdk-8-jre=1.8.0_292

Switch the default java
$ sudo update-alternatives --config java
*            /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java   1081

Checking the default java
    $ java -version

openjdk version "1.8.0_292"
OpenJDK Runtime Environment (build 1.8.0_292-8u292-b10-0ubuntu1~18.04-b10)
OpenJDK 64-Bit Server VM (build 25.292-b10, mixed mode)
Run the UBGC.jar
$ java -jar UBCG.jar 
      ###############################
      #         UBCG ver. 3.0       #
      ###############################

Java error when trying to run UBCG jar (java.lang.ClassNotFoundException)

One Answer

Add your own answers!

Ask a Question