Encountered a NullPointerException in https://github.com/qos-ch/logback/blob/v_1.2.11/logback-classic/src/main/java/ch/qos/logback/classic/spi/ThrowableProxy.java#L99 when https://github.com/qos-ch/logback/blob/v_1.2.11/logback-classic/src/main/java/ch/qos/logback/classic/spi/ThrowableProxy.java#L123-L134 returns null. 

This was introduced in 1.2.11 with commit https://github.com/qos-ch/logback/commit/398aa4bd8f2bc0bb7f1465e8f7aca418c4464c15 and 1.2.10 does not have this problem.

Note: The comment regarding Java 7 in https://github.com/qos-ch/logback/blob/v_1.2.11/logback-classic/src/main/java/ch/qos/logback/classic/spi/ThrowableProxy.java#L96 is a bit misleading, since it will execute on Java >= 7.