logback-android/src/main/java/ch/qos/logback/core/util/OptionHelper.java
public static String getSystemProperty(String key, String def) {
    try {
      return System.getProperty(key, def);
    } catch (SecurityException e) {
      return def;
    }
  }
public static String getSystemProperty(String key, String def) {
    try {
      return System.getProperty(key, def);
    } catch (SecurityException e) {
      return def;
    }
  }
Very similar to <code>System.getProperty</code> except that the
{@link SecurityException} is absorbed.

@param key The key to search for.
@param def The default value to return.
@return the string value of the system property, or the default value if
there is no property with that key.