code: public final void setOptimizationLevel(int optimizationLevel)
      {
          if (sealed) onSealedMutation();
          if (optimizationLevel == -2) {
              // To be compatible with Cocoon fork
              optimizationLevel = -1;
          }
          checkOptimizationLevel(optimizationLevel);
          if (codegenClass == null)
              optimizationLevel = -1;
          this.optimizationLevel = optimizationLevel;
      }
docs: Set the current optimization level.
  <p>
  The optimization level is expected to be an integer between -1 and
  9. Any negative values will be interpreted as -1, and any values
  greater than 9 will be interpreted as 9.
  An optimization level of -1 indicates that interpretive mode will
  always be used. Levels 0 through 9 indicate that class files may
  be generated. Higher optimization levels trade off compile time
  performance for runtime performance.
  The optimizer level can't be set greater than -1 if the optimizer
  package doesn't exist at run time.
  @param optimizationLevel an integer indicating the level of
  optimization to perform
  @since 1.3