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From:Eric Eldred Date:March 26 1999 6:35am
Subject:null pointer exception (mm jdbc)
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sorry I'm a real beginner here and have studied the docs,]
books, and previous postings without success.

i am trying to use the mm jdbc driver with:
v1.3 (1998-08-25) of Driver.java
v9.13 (3.21.29a-gamma) of mysql for win95.
jdk1.2 for win32.

mysql works fine by starting the mysqld
and from the mysql console.  my TCP works fine
and I can ping localhost or 192.168.1.1, my IP.

then i installed the Driver.class etc under 
d:\jdk1.2\org\gjt\mm\mysql\
and wrote a simple java program to open the
connection to my testdb:

...
Connection conn = null;
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
Properties P = System.getProperties();
P.put("jdbc.drivers", "org.gjt.mm.mysql.Driver");
System.setProperties(P);
conn =
DriverManager.getConnection("jdbc:mysql://localhost:3306/testdb");
...etc

when i try to run it it gives me no SQLException,
but rather a null pointer exception when i try to
close the connection, with a stack
trace that points to 
Exception in thread "main" java.lang.ClassFormatError:
 org/gjt/mm/mysql/Connection (Invalid start_pc/length in local var
table)

(i think this refers to the Connection.class that mm
supplies, and which is called by Driver, and
which is labeled as not to be used by user.)

i tried adding null user and password fields to the
getConnection string, and using the IP address and
so on, as previously recommended, but it continues
to give me the same error.  please, any suggestions?

may i suggest that all this could use some better
documentation, with more specific examples that work,
and some clear pointers on installation?
Thread
null pointer exception (mm jdbc)Eric Eldred26 Mar
  • Re: null pointer exception (mm jdbc)Christian Mack26 Mar