Attempting to follow the instructions in README.md to add the LoggingHandler via logging.properties it seems this always fails as of v3.6.0 with a NullPointerException due to the change introduced in bb25d5d. With a no-arg constructor, options will be null and line 244 will fail to call the getAutoPopulateMetadata() on that null reference.

To be able to the the mechanism where qualified classnames of subclasses to java.util.logging.Handler are added to a handlers property in logging.properties, a public no-arg constructor needs to be available. There is also a code example with a no-arg constructor in README.md

Steps to reproduce:

• Add a call new LoggingHandler() anywhere, for example in a unit test and run it

Expected outcome:
No exception raised

Actual outcome:
A NullPointerException is raised:

java.lang.NullPointerException
	at com.google.cloud.logging.LoggingHandler.<init>(LoggingHandler.java:244)
	at com.google.cloud.logging.LoggingHandler.<init>(LoggingHandler.java:193)
	at com.google.cloud.logging.LoggingHandler.<init>(LoggingHandler.java:162)