java, jre, jdk, java.sql or what?

[eindhoven44]

Yes, I am a complete noob but know enough to be a dangerous noob.

So I have Linux xx.xx.com 2.6.9-5.ELsmp #1 SMP Wed Jan 5 19:30:39 EST 2005 i686 i686 i386 GNU/Linux installed.

I think that means I have enterprise level Redhat 2.6 or would it be refered to as 6.2? running at i686 level or i386?

I need to install Java so that it can connect to a SQL database running on a 2K3 Server. I though it would be simple when I built this in my head.

Here is some of my output. I think I installed Java correctly but nothing runs, not even "Hello World"

[root@bling etc]# java -version
java version "1.4.2_05" Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_05-b04) BEA WebLogic JRockit(TM) 1.4.2_05 JVM R24.4.1-1 (build ari-38317-20041124-1225-linux-ia32, Native Threads, GC strategy: parallel)

~I am interpretting this to say that I installed Java 1.4.2_05

This is what I get when I do this...
[root@bling etc]# java help
java.lang.NoClassDefFoundError: help

[root@bling etc]# whereis java
java: /usr/bin/java /etc/java /usr/lib/java /usr/share/java /usr/share/man/man1/java.1.gz

So I tried to set the path as
[root@bling etc]# PATH=$PATH:./usr/bin/java

still no go.

I modified /etc/java/java.conf to set JAVA_LIBDIR=/usr/bin/java

That didnt seem to go over either.

Trying to find java rpm gives me this,
[root@bling etc]# rpm -q java
package java is not installed

So, I dont get it. Is it there and not configured or not there.

Plus, I dont know if I need just javaRE, JDK, java.SQL or Java server even. There will be apps written in java connecting to the SQL side (Hopefully by using SQL2Java)...and from other threads I hear I need java server...or is it just java.SQL?

I dont need an onion to cry. I am already there.

In short I am lost like a fart in a whirl wind. Any help to clear the air would be great.

Thanks.

[Cabhan]

Alrighty.

First off, you are running Linux kernel 2.6.9. The Red Hat version you are running may be something very different (for instance, I run kernel 2.6.17, but my Gentoo version is 2006.1).

Now then, the "java help" error message is saying that you are trying to run the class "help", which is not written. To get help on the command "java", run the command "man java".

Nextly, I know very little about the database side of Java, but here is the difference between the JRE and the JDK:

The JRE allows you to run Java applications that you are given. This includes the VM and the interpreter, but not the compiler or the standard library.

The JDK includes the JRE as well as the compiler and library. If you are going to be writing Java applications, you need the JDK.

I will let another Java expert answer the server question.

[eindhoven44]

Cabhan ~ thanks for clarifying some of these things for me. The version bit was clearly confusing for me.

I will go get the sun jdk then and install the rpm.

Hopefully I can get a database answer. I am thinking I need to run java.sql too but I really am not certain given that the SQL Server is outside the box.

Thanks again.