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javamysqlexceptionjdbcclassloader

ClassNotFoundException in MySQL Connector/J

This has been asked before but I cannot find the answer I need.

1) Using Class.forName("com.mysql.java.Driver") in the eclipse IDE all works well. I load the correct jar (mysql-connector-java-5.1.20-bin.jar), no exception.

When I create a jar for my app a1.jar and double click the jar, I get the ClassnotFoundException.

I created a .bat file in Windows XP with

java -classpath c:\temp\mysql-connector-java-5.1.20-bin.jar -jar c:\temp\a1.jar the app statrs with the same exception.

Furthermore using System.getProperty ("java.class.path") shows c:\temp\a1.jar whilst in the IDE I can see several directories

Solution

  • If you are executing a file using -jar, then any external classpath (either provided on the commandline or the environment) is ignored. It only looks to the Class-path: entry in the META-INF/MANIFEST.MF file. If the MySQL jar isn't specified there, it won't load it.