(in ExampleApp7.java)

...

// To reduce overheads, disable "automatic-activation" feature.
Map<String, Object> optionMap = new HashMap<String, Object>();
optionMap.put("AUTOMATIC_ACTIVATION_ENABLED", false);

...

// Activate the engine manually.
engine.activate();

...

// Execute the expression (or script) repetitively with changing the value of "x".
for (int i=0; i<REPETITION_COUNT; i++) {
    plugin.x = i * 0.125;
    double valueOfExpression = (double)engine.executeScript(expression);
    sum += valueOfExpression;
}

...

// Deactivate the engine manually.
engine.deactivate();