how i put rt.jar thats is missing?

[Prilicat]

that's the error.

[FirephoenixX02]

use another java version i get this error on java > 8, so try it with java 8

[post1114]

You need to add a JVM parameter
Just like this
java -cp "c:\path\to\your\jre\lib\rt.jar" -jar caesium.jar
Note: The rt.jar file is only available in the Java Runtime Environment series.
Following this plan should solve your problem.