public void setTargetExecutor(Executor targetExecutor) {
        this.targetExecutor = targetExecutor;
    }
Sets target Executor instance that will actually execute the subject-associated Runnable instances.

@param targetExecutor the target Executor instance that will actually execute the subject-associated Runnable
                      instances.
core/src/main/java/org/apache/shiro/concurrent/SubjectAwareExecutor.java