jodd-core/src/main/java/jodd/system/SystemUtil.java
public static boolean getBoolean(final String name, final boolean defaultValue) {
		String value = get(name);
		if (value == null) {
			return defaultValue;
		}

		value = value.trim().toLowerCase();

		switch (value) {
			case "true" :
			case "yes"  :
			case "1"    :
			case "on"   :
				return true;
			case "false":
			case "no"   :
			case "0"    :
			case "off"  :
				return false;
			default:
				return defaultValue;
		}
	}
public static boolean getBoolean(final String name, final boolean defaultValue) {
		String value = get(name);
		if (value == null) {
			return defaultValue;
		}

		value = value.trim().toLowerCase();

		switch (value) {
			case "true" :
			case "yes"  :
			case "1"    :
			case "on"   :
				return true;
			case "false":
			case "no"   :
			case "0"    :
			case "off"  :
				return false;
			default:
				return defaultValue;
		}
	}
Returns system property as boolean.