Oracle SQL Developer and JDK

After Oracle SQL Developer was installed (without including JDK in the pack) on my new laptop, its first launch creates file C:\Users\user_ID\AppData\Roaming\sqldeveloper\product.conf, which specifies and saves the path of Java. In the first run, it brings up a popup box says "Please specify the path to the Java JDK home (e.g. ... ...)". The correct path has to be entered here for SQL Developer to fire up. On my laptop, after I click on OK to accept default path C:\Program Files (x86)\Java\jdk18, the popup box goes away. Then nothing shows up and it seems at a dead end.

During troubleshooting, I learned my laptop has two Java installation locations, which leads some confusion. The one in C:\Program Files\Java\jdk18 is a 64-bit that was requested and installed for being used by SQL Developer. SQL Developer installed is a 64-bit application and needs 64-bit Java. After I entered C:\Program Files\Java\jdk18 in the popup box, SQL Developer 21.4.3 worked and the Properties info can be viewed by Help -> About.

It the first launch, it asks if you want to import preference from previous version. I copied over folder C:\Users\user_ID\AppData\Roaming\SQL Developer\system20.4.1.407.0006 from my old laptop, and let import copy SQL Developer setups from old computer. It keeps all database connections (ID & password). This is exactly what I want.

SQL Developer connection info is saved in location C:\Users\user_ID\AppData\Roaming\SQL Developer\systemX.X.X.X.X\o.jdeveloper.db.connection\connections. It is a good practice to back it up from time to time.

-- How to fine JAVA HOME and Java info on Windows?

On the Windows machine, use "cmd" window. 

Microsoft Windows [Version 10.0.19044.3324]

(c) Microsoft Corporation. All rights reserved.

c:\> echo %JAVA_HOME%

C:\Program Files\Java\jdk18;C:\Program Files (x86)\Java\jdk18

It shows two Java installations. The one in C:\Program Files\Java\jdk18 is a 64-bit,

c:\>cd \Program Files\Java

c:\Program Files\Java>dir

 ... ...

08/14/2023  09:21 AM    <DIR>          jdk18

08/14/2023  09:12 AM    <DIR>          jre8

c:\Program Files\Java>cd jdk18

c:\Program Files\Java\jdk18>dir /A:D

... ...

08/14/2023  09:21 AM    <DIR>          bin

08/14/2023  09:21 AM    <DIR>          include

08/14/2023  09:21 AM    <DIR>          jre

08/14/2023  09:21 AM    <DIR>          legal

08/14/2023  09:21 AM    <DIR>          lib

c:\Program Files\Java\jdk18>cd bin

c:\Program Files\Java\jdk18\bin>java.exe -version

java version "1.8.0_281"

Java(TM) SE Runtime Environment (build 1.8.0_281-b09)

Java HotSpot(TM) 64-Bit Server VM (build 25.281-b09, mixed mode)

The JDK in C:\Program Files (x86)\Java\jdk18 is 32-bit.

c:\Program Files\Java\jdk18>cd \Program Files (x86)\Java\jdk18

c:\Program Files (x86)\Java\jdk18>cd bin

c:\Program Files (x86)\Java\jdk18\bin>java -version

java version "1.8.0_281"

Java(TM) SE Runtime Environment (build 1.8.0_281-b09)

Java HotSpot(TM) Client VM (build 25.281-b09, mixed mode)

-- How to find out the Windows is 64-bit or 32-bit?

Go to Start > Settings (a wheel icon) > System > About

System Type: 64-bit operating system, x64-based processor