Logback - How to log the simple name of an exception separately

ProtossShuttle :

Is there any way you can log only the simple name of an exception without explicitly retrieving it from the code?

For example, by calling

log.error(exception);

with a logback pattern

%d{yyyy-MM-dd}|%-5level|%m%n

instead of just logging the exception stack traces

2018-01-01|ERROR|
mainPackage.foo.bar.RocketExplosionException: Houston we have a problem
  at mainPackage.foo.bar.TestThrower.fire(TestThrower.java:22)
  at mainPackage.foo.bar.TestThrower.readyToLaunch(TestThrower.java:17)
  at mainPackage.ExceptionLauncher.main(ExceptionLauncher.java:38)

A separate column with the simple name of the exception is expected to be logged

2018-01-01|ERROR|RocketExplosionException|
mainPackage.foo.bar.RocketExplosionException: Houston we have a problem
  at mainPackage.foo.bar.TestThrower.fire(TestThrower.java:22)
  at mainPackage.foo.bar.TestThrower.readyToLaunch(TestThrower.java:17)
  at mainPackage.ExceptionLauncher.main(ExceptionLauncher.java:38)

glytching :

You could write your own custom conversion specifier.

To do this, you would declare a conversion rule in your logback.xml for the %exname symbolic like so:

<?xml version="1.0" encoding="UTF-8" ?>
<configuration>
    <conversionRule conversionWord="exname" converterClass="com.foo.ExceptionNameConverter" />

    ...

</configuration>

Then declare ExceptionNameConverter like so:

import ch.qos.logback.classic.pattern.ThrowableProxyConverter;
import ch.qos.logback.classic.spi.IThrowableProxy;

public class ExceptionNameConverter extends ThrowableProxyConverter {
    @Override
    protected String throwableProxyToString(IThrowableProxy tp) {
        return tp.getClassName();
    }
}

Now, using this pattern:

%d{yyyy-MM-dd}|%-5level|%exname|%m%n

The following log statement:

logger.error("Boom!", new RuntimeException("ouch"));

Will emit:

2018-09-26|ERROR|java.lang.RuntimeException|Boom!