java - How to fix sealing violation from a library? sealing violation: package org.lwjgl.opengl is sealed -

while setting project template slick2d based projects following instructions here:slick2d wiki using provided code testing setup here @ run-time keep getting giant block of sealing errors. thought problem stems version of ljgwl.jar in both libraries, slick requires both in order function properly. how can resolve this?

package sealing java feature implemented in part in jar file format. discussed in several places, including in oracle's java tutorial, bottom line when package sealing enabled in jar's manifest, no classes belonging package can appear in other jar file.

my thought problem stems version of ljgwl.jar in both libraries, slick requires both in order function properly.

i'm not sure mean "library", not java concept. suspect, however, you're trying somehow have ljgwl.jar files 2 separate sources, , you've put both project classpath. indeed problem, , more package sealing. can, in fact, thankful sealing errors, may have saved subtler, more difficult diagnose runtime errors.

how can resolve this?

you should have 1 copy of lwjgl in classpath, regardless of requirements enforced package sealing, , regardless of how classes packaged in jar files. looks slick2d distribution may come copy of lwjgl -- in case, it's wisest use one. long it's in classpath (as must anyway slick2d use it), class anywhere in application can use it.

it gets tricky if need contend inconsistent requirements lwjgl version, or if have obtained jar incorporates lwjgl classes along else, doesn't change bottom line: must choose 1 version of lwjgl, use version exclusively within application, , include 1 copy of in classpath.