Logger.traceEntry throws NPE on null arguments and eagerly evaluates toString

[SpaceLeam]

Hi,

I noticed that Logger.traceEntry in the Scala wrapper currently lacks the safety checks present in the Java Core API, leading to potential crashes.

There are two issues here:

1. NPE Risk: It calls .toString on params.head immediately without checking if the parameter is null.
2. Eager Evaluation: It evaluates the arguments before checking if the TRACE level is enabled. This means if an object has a heavy or faulty toString, it triggers an exception even if logging is explicitly disabled (e.g., set to FATAL).

Reproduction:

val logger = Logger(classOf[MyClass])

// 1. Causes NullPointerException
logger.traceEntry(null, null) 

// 2. Causes crash (or performance hit) even if Level is FATAL/OFF
// because toString is called before the level check.
logger.traceEntry(new Object { 
  override def toString = throw new RuntimeException("Boom") 
}, "dummy")

Proposed Fix:
The method should check delegate.isTraceEnabled first to ensure lazy evaluation, and handle null parameters gracefully to match the fail-safe behavior of Log4j Core.

I am working on a PR to fix this.

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