I tested again with Ubuntu quantal and netbeans now runs fine, with both OpenJDK 6 and 7:
$ /usr/local/netbeans-7.1/bin/netbeans --jdkhome /usr/lib/jvm/java-7-openjdk-i386/
$ /usr/local/netbeans-7.1/bin/netbeans --jdkhome /usr/lib/jvm/java-6-openjdk-i386/
$ /usr/lib/jvm/java-7-openjdk-i386/bin/java -version java version "1.7.0_07" OpenJDK Runtime Environment (IcedTea7 2.3.2) (7u7-2.3.2a-1ubuntu1) OpenJDK Server VM (build 23.2-b09, mixed mode)
$ /usr/lib/jvm/java-6-openjdk-i386/bin/java -version java version "1.6.0_24" OpenJDK Runtime Environment (IcedTea6 1.11.4) (6b24-1.11.4-3ubuntu1) OpenJDK Server VM (build 20.0-b12, mixed mode)
I tested again with Ubuntu quantal and netbeans now runs fine, with both OpenJDK 6 and 7:
$ /usr/local/ netbeans- 7.1/bin/ netbeans --jdkhome /usr/lib/ jvm/java- 7-openjdk- i386/
$ /usr/local/ netbeans- 7.1/bin/ netbeans --jdkhome /usr/lib/ jvm/java- 6-openjdk- i386/
$ /usr/lib/ jvm/java- 7-openjdk- i386/bin/ java -version 3.2a-1ubuntu1)
java version "1.7.0_07"
OpenJDK Runtime Environment (IcedTea7 2.3.2) (7u7-2.
OpenJDK Server VM (build 23.2-b09, mixed mode)
$ /usr/lib/ jvm/java- 6-openjdk- i386/bin/ java -version 11.4-3ubuntu1)
java version "1.6.0_24"
OpenJDK Runtime Environment (IcedTea6 1.11.4) (6b24-1.
OpenJDK Server VM (build 20.0-b12, mixed mode)