The red error message will tell you the type of error up near the top, and sometimes a little message that can be helpful.
However, perhaps more important, the red error message will tell you what LINE of your program the error occurred on. (This isn't necessarily the line that had the bug-- the bug could have been setting an inappropriate value earlier, which caused the error to happen later when that value got used...) However, it's generally helpful to know what line number the error occurred on.
The red text lists multiple line numbers, because it shows what method CALLED what other method, which caused the error. These line numbers / files are listed in reverse order of which method called which. Sometimes the error happened inside one of the standard Java library methods... so find the FIRST line that mentions YOUR .JAVA PROGRAM FILE, and look at what line number that mentions.