public final boolean getBoolean(String key, boolean defaultValue) {
        return asBoolean(get(key), defaultValue);
    }
Gets a property as a boolean.
This will return true only if the value is either the empty string,
or any Object which has a toString which is case-insensitive equal to "true"

@param defaultValue the value to return if this property is null
container-core/src/main/java/com/yahoo/processing/request/Properties.java