java - SLF4J-Logback print root cause message -

i using slf4j logback log error messages. 1 of observations of root cause requires tostring() instead of getmessage(). example, if exception wrapped under another, slf4j prints 'null' of root cause instead of exception message indirectly referenced in tostring(). java util library logs fine. however, have use slf4j-logback. there way overrides default behaviour of slf4j , logback.

class testexception extends exception         {             private string exceptioncode;             private string exceptionmessage;              @override             public string tostring()             {                 return "testexception [exceptioncode=" + exceptioncode + ", exceptionmessage=" + exceptionmessage + "]";             }         }          try         {             testexception testexception = new testexception();             testexception.exceptioncode = "test exception code";             testexception.exceptionmessage = "test exception message";             throw new ioexception("io message", testexception);         }         catch (exception e)         {             logger.error("error message ", e);             java.util.logging.logger.getanonymouslogger().log(java.util.logging.level.severe, "error message", e);         } 

output presents with:

// slf4j logging java.io.ioexception: io message     @ test.test.testmethod(test.java:224)     @ test.test.main(test.java:119) caused by: test.test$1testexception: null     @ test.test.testmethod(test.java:221)     ... 1 common frames omitted nov 17, 2016 11:52:04 test.test testmethod  // java util logging severe: error message java.io.ioexception: io message     @ test.test.testmethod(test.java:224)     @ test.test.main(test.java:119) caused by: testexception [exceptioncode=test exception code, exceptionmessage=test exception message]     @ test.test.testmethod(test.java:221)     ... 1 more