I have been using 30EA3 (3.0.03.45) for several months.
Today I downloaded and installed EA4. Downloaded no-jre version and unziped to empty directory. It asked for path to java and if I want to import connections. When I tried to open a connection I was using with EA3 a couple of minutes earlier, it failed with dialog box:
BTW, I am running the 32 bit version on an AMD64 with Win7 Ultimate. I use Instant Client 11.1. I tried Instant Client 11.2, and also tried the with-jre version with no luck. EA3 still works, as does 2.1
Is your Preferences>Database>Advanced setting for "Use OCI/Thick driver" checked? If so try unchecking it and try connecting again. This worked for me without changing the client or any environment settings.
I am getting the same error with the 3.0.04.34 version of SQL Developer as I got with the 3.0.03.97. So, I'm still using 3.0.03.45. This time, I exited the running sqldeveloper 3.0.03.45, and started the sqldeveloper exe for 3.0.04.34 which I just downloaded and unzipped. It asked to import settings. When I try to open the connect to scott/tiger@//lambda/ora10 (where lambda is my local db server), I get this unhelpful java error. Debugging java and jdbc are not in my area of interest or expertise.