Java "var cannot be resolved to a type" - JDK 13.0

[hkuadithya]

Issue Type: Bug

VSCode Java extension seems to raise error while using var data type (type inference for local variables was introduced way back with Java 10). Running the project also seems to fail while using var datatype.

There's absolutely no problem with my Java environment. Compiling and running the same Java file using javac and java succeeds in command line. This works fine with IntelliJ IDEA as well.

Is there some setting or configuration I need to change? Screenshot of Java runtime configuration page below:-

Java environment details:

java 13.0.2 2020-01-14
Java(TM) SE Runtime Environment (build 13.0.2+8)
Java HotSpot(TM) 64-Bit Server VM (build 13.0.2+8, mixed mode, sharing)

Error

Configure java runtime - JDK 13

---

Extension version: 0.8.1
VS Code version: Code 1.42.1 (c47d83b293181d9be64f27ff093689e8e7aed054, 2020-02-11T14:45:59.656Z)
OS version: Windows_NT x64 10.0.18362

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-7500U CPU @ 2.70GHz (4 x 2904)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on oop_rasterization: disabled_off protected_video_decode: enabled rasterization: enabled skia_renderer: disabled_off surface_control: disabled_off surface_synchronization: enabled_on video_decode: enabled viz_display_compositor: enabled_on viz_hit_test_surface_layer: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	15.91GB (8.79GB free)
Process Argv
Screen Reader	no
VM	0%

[akaroml]

Thanks for reaching out. The Java 13 syntax needs to be enabled explicitly. If you are using Maven, please follow the instructions:
https://sandny.com/2019/10/08/enable-the-preview-feature-in-java-13-with-maven/

[hkuadithya]

@akaroml Hello. I'm not using Maven. I was just testing a simple Program in Java.
Besides, I didn't have to enable any preview features (--enable-preview) while running javac and java. The program had var datatypes.

javac TestProgram.java
java TestProgram

Variable Type inference was introduced a long time ago in Java. I'm not sure why these errors are flaring up now.

Is there something setting we can change for non-maven simple java programs? Any setting in launch.json? Does this issue persist for all versions >= Java 10? If so, please assign a bug label for tracking.

[akaroml]

OK. Running without Maven should also work. var was introduced a while ago, so it should be supported.

The next step is to verify the JDK version. You can use the command: Java: Configure Java Runtime to show the actual JDK that is used by VS Code. 11+ should be your current JDK like this:

[hkuadithya]

@akaroml
It looks like you missed the details in the description of this issue.
I had already posted the screenshot of Configure Java runtime when I raised this Bug. Please check.

java.home and other has been configured to the path of C:\Program Files\Java\jdk-13.0.2.

It looks like your team does not have much context regarding this bug. If possible, please assign this bug to the appropriate RedHat team since they maintain the "Language Support for Java" extension.

Also, since this is a valid issue, please assign "Bug" label for greater visibility.

[hkuadithya]

@akaroml

I have assigned this bug to the RedHat team. Issue: redhat-developer/vscode-java#1288

Closing this issue here.

[alama000]

Had same error. To avoid this error, the first thing when creating a Java Project, we need to choose the JRE option as 'Use an execution environment JRE' instead of choosing 'Use a project specific JRE'.