Looks like some kind of backward compatibility break on the JDK side - 
DefaultAdaptor doesn't implement a bunch of methods on its parent interface.  
I'll attach a hacked patch that enables me to build NetBeans on JDK 6, though 
it's just implemented to stub the new methods.  I'm guessing some sort of 
super-high priority JDK bug should be filed about this - if you do file it, 
please note issue number before closing.

compile-lib:
    [mkdir] Created dir: C:\space\winsys\db\build\lib-classes
    [javac] Compiling 60 source files to C:\space\winsys\db\build\lib-classes
   [repeat] 
C:\space\winsys\db\libsrc\org\netbeans\lib\ddl\adaptors\DefaultAdapt
or.java:30: org.netbeans.lib.ddl.adaptors.DefaultAdaptor is not abstract and 
doe
s not override abstract method getFunctionParameters
(java.lang.String,java.lang.
String,java.lang.String,java.lang.String) in java.sql.DatabaseMetaData
   [repeat] public class DefaultAdaptor implements DatabaseMetaDataAdaptor, 
Seri
alizable {
   [repeat]        ^
   [repeat] 1 error
  [nbmerge] Failed to build target: all-db

BUILD FAILED
C:\space\winsys\nbbuild\build.xml:562: The following error occurred while 
execut
ing this line:
C:\space\winsys\nbbuild\build.xml:557: The following error occurred while 
execut
ing this line:
C:\space\winsys\nbbuild\build.xml:607: The following error occurred while 
execut
ing this line:
C:\space\winsys\db\build.xml:20: Compile failed; see the compiler error output 
f
or details.