Recently solved a mystery that puzzled me a couple of times when installing the newer version 4 of sqlDeveloper in a Windows 10 Pro environment.
In the past with version 3 and lower the java path that sqldeveloper used was set by assigning a value to SetJavaHome in the <whatever your path to sqldeveloper>\bin directory sqldeveloper.conf file.
With version 4 of sqldeveloper that is no longer true. You instead modify the same SetJavaHome variable but now the file that you changed it in is product.conf.
Product.conf is located something like as follows (replace Michael with your username below):
C:\Users\Michael\AppData\Roaming\sqldeveloper\4.1.3\product.conf
So if you’re getting error like this:
Unable to launch the Java Virtual Machine
Located at path:
C:/Program Files/sqldeveloper/jdk/jre/bin/server/jvm.dll
The reason is SetJavaHome in the file C:\Users\Michael\AppData\Roaming\sqldeveloper\4.1.3\product.conf is not set properly, and if you are finding old posts out there telling you to modify sqldeveloper.conf – with version 4 of sqldeveloper and higher – that file is no longer used – even though the environment variable is still there – it is ignored.