I was trying to play MineCraft in my hackintosh with Mac OS 10.5.7 (really old huh?) and running java -jar launcher.jar of the game kept throwing:

Exception in thread "main" java.lang.NoSuchMethodError: java.lang.String.isEmpty()Z
	at org.spoutcraft.launcher.SettingsHandler.loadHashMap(SettingsHandler.java:199)
	at org.spoutcraft.launcher.SettingsHandler.checkProperty(SettingsHandler.java:329)
	at org.spoutcraft.launcher.SettingsUtil.getProperty(SettingsUtil.java:114)
	at org.spoutcraft.launcher.SettingsUtil.getMemorySelection(SettingsUtil.java:85)
	at org.spoutcraft.launcher.Main.main(Main.java:102)

After researching I found that the problem was, somehow, that Java was trying to use version 5, and the Launcher of my game was coded for version 6. Easy fix then!

1) Look up in spotlight for Java Preferences and open it.

2) Drag and drop Java SE 6 from 2nd line to the top one. Do same thing for both Java Applets and Applications.

That should fix it. Helpful? Promote this article! Still having errors? Comment below!