Merge pull request #7327 from suddenwhipvapor/master

Add instruction to select JDK version at build time

docs/build.md

@@ -5,8 +5,8 @@
    ```sh
    git clone https://github.com/bisq-network/bisq
    # if you intend to do testing on the latest release, you can clone the respective branch selectively, without downloading the whole repository
-   # for the 1.9.3 release, you would do it like this:
-   git clone --recurse-submodules --branch release/v1.9.3 https://github.com/bisq-network/bisq
+   # for the 1.9.18 release, you would do it like this:
+   git clone --recurse-submodules --branch release/v1.9.18 https://github.com/bisq-network/bisq
    cd bisq
    ```
 
@@ -35,6 +35,18 @@
    javac -version
    ```
 
+   If you have multiple JDK versions installed, check which one Gradle will use, with:
+
+   ```sh
+   ./gradlew --version
+   ```
+
+   and if the version number on the JVM line is not a supported one, you can pick the correct JDK at runtime with this syntax (verify your system path):
+
+   ```sh
+   ./gradlew build -Dorg.gradle.java.home=/usr/lib/jvm/java-11-openjdk-amd64/
+   ```
+
 If you do not have JDK 11 installed, check out scripts in the [scripts](../scripts) directory or download it manually from https://jdk.java.net/archive/.
 
 ## Running Bisq