copy jar file to YOUR_JDK_HOME/jre/lib/ext open configuration file YOUR_JDK_HOME/jre/lib/security/java.security and add there security.provider.10=org.wildfly.security.test.CustomElytronProvider to section of security providers. Please replace number 10 to applicable. Try to start EAP - ./bin/standalone.sh You can see this error message Exception in thread "main" java.lang.NoClassDefFoundError: org/wildfly/security/test/CustomCredentialStore at org.wildfly.security.test.CustomElytronProvider.putCustomCredentialStoreProviderImplementations(CustomElytronProvider.java:48) at org.wildfly.security.test.CustomElytronProvider.<init>(CustomElytronProvider.java:42) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:422) at java.lang. Class .newInstance( Class .java:442) at sun.security.jca.ProviderConfig$2.run(ProviderConfig.java:221) at sun.security.jca.ProviderConfig$2.run(ProviderConfig.java:206) at java.security.AccessController.doPrivileged(Native Method) at sun.security.jca.ProviderConfig.doLoadProvider(ProviderConfig.java:206) at sun.security.jca.ProviderConfig.getProvider(ProviderConfig.java:187) at sun.security.jca.ProviderList.loadAll(ProviderList.java:282) at sun.security.jca.ProviderList.removeInvalid(ProviderList.java:299) at sun.security.jca.Providers.getFullProviderList(Providers.java:173) at java.security.Security.insertProviderAt(Security.java:360) at java.security.Security.addProvider(Security.java:403) at org.jboss.modules.Main.lambda$main$0(Main.java:503) at java.security.AccessController.doPrivileged(Native Method) at org.jboss.modules.Main.main(Main.java:502)