jSystemThemeDetector: [MacOS Catalina] NPE: Couldn't execute theme name query with the Os

Hi, Just noticed this NPE, wondered if this is normal or an OS-related issue somehow. My code calls OsThemeDetector.getDetector().isDark() at some point, and the full stack trace reads

[AWT-EventQueue-0] ERROR com.jthemedetecor.MacOSThemeDetector - Couldn't execute theme name query with the Os
java.lang.NullPointerException
	at java.base/java.util.regex.Matcher.getTextLength(Matcher.java:1770)
	at java.base/java.util.regex.Matcher.reset(Matcher.java:416)
	at java.base/java.util.regex.Matcher.<init>(Matcher.java:253)
	at java.base/java.util.regex.Pattern.matcher(Pattern.java:1133)
	at com.jthemedetecor.MacOSThemeDetector.isDarkTheme(MacOSThemeDetector.java:96)
	at com.jthemedetecor.MacOSThemeDetector.isDark(MacOSThemeDetector.java:86)

More specifically, the NPE is due to the following call (within the isDark() method) returning the ‘0’ byte:

Foundation.invoke(userDefaults, "objectForKey:", Foundation.nsString("AppleInterfaceStyle"))

I should mention that this happens during daytime (and luckily isDark() returns false), so no harm done (besides an avoidable(?) pollution of the logger)

Any clue where that might come from?

In case this helps: using version 3.7 @ openjdk11 @ macOS 10.15.7

About this issue

Original URL
State: open
Created 3 years ago
Reactions: 1
Comments: 15

Most upvoted comments

In the meantime, does anyone know how to silence the logger?

I don’t fully understand how the logger works. I’ve tried using
java.util.logging.Logger.getLogger("com.jthemedetecor.MacOSThemeDetector").level = Level.OFF
	java.util.logging.Logger.getLogger("com.jthemedetecor").level = Level.OFF
in my code, but that does nothing.

Whenever I search “how to disable a org.slf4j.Logger” people are talking about things like log4j. It’s very confusing. I don’t think I have log4j installed, but just in case I tried adding a “log4j.properties” to my classpath with log4j.logger.com.jthemedetecor=OFF but that is not doing anything either.

use the following two lines in log4j2.properties

logger.jthemedetecor.name = com.jthemedetecor
logger.jthemedetecor.level = off

reference

nybbs2003 on Jul 4, 2022

It sounds like you don’t want logging at all, in which case you should add sl4j-nop (no-op) logger to your dependencies. I only know log4j with that if you have a logging configuration (log4j2.xml) on your classpath it should ignore libraries that are not configured. This library uses logback with sl4j I have no knowledge of that but it shouldn’t matter if you are not using it.

ctipper on May 22, 2022