中海达gps怎么校点:新手请教JAVA安装问题

我安装的是j2sdk1.5并且设置了环境变量PATH
C:\Program Files\Java\j2sdk1.5.0\bin
并且在DOC下运行javac出现以下内容：

Microsoft Windows XP [版本 5.1.2600]
(C) 版权所有 1985-2001 Microsoft Corp.

C:\Documents and Settings\yujun>javac
Usage: javac <options> <source files>
where possible options include:
-g Generate all debugging info
-g:none Generate no debugging info
-g:{lines,vars,source} Generate only some debugging info
-nowarn Generate no warnings
-verbose Output messages about what the compiler is doing
-deprecation Output source locations where deprecated APIs are u
sed
-classpath <path> Specify where to find user class files
-cp <path> Specify where to find user class files
-sourcepath <path> Specify where to find input source files
-bootclasspath <path> Override location of bootstrap class files
-extdirs <dirs> Override location of installed extensions
-endorseddirs <dirs> Override location of endorsed standards path
-d <directory> Specify where to place generated class files
-encoding <encoding> Specify character encoding used by source files
-source <release> Provide source compatibility with specified release

-target <release> Generate class files for specific VM version
-version Version information
-help Print a synopsis of standard options
-X Print a synopsis of nonstandard options
-J<flag> Pass <flag> directly to the runtime system

C:\Documents and Settings\yujun>

请问我还得怎么做？我还需要安装什么软件？
如果是的话，给我下载地址和详细的安装方法