protected static void assertState(final boolean validState, final String message,
      final Object... args) {
    if (!validState) {
      throw new IllegalStateException(String.format(message, args));
    }
  }
Asserts whether state, based on the evaluation of a conditional expression, passed to this
assertion is valid.

@param validState a boolean value indicating the evaluation of the expression from which the
       conditional state is based. For example, a caller might use an expression of the form
       (initableObj.isInitialized()).
@param message a String values used as the message when constructing an IllegalStateException.
@param args Object arguments used to populate placeholder's in the message.
@throws IllegalStateException if the conditional state is not valid.
@see java.lang.String#format(String, Object...)
geode-gfsh/src/main/java/org/apache/geode/management/internal/web/shell/HttpOperationInvoker.java