Use the correct runtime to validate the JVM versions between the debugger and debuggee

[testforstephen]

When attaching to an existing debuggee program, its runtime version may be different with the one that the debugger used to build your project. Although the debugger still works when the JDK mismatches. But stepping into the JDK system library, the native library source line may be not consistent with the remote one and cause the line mismatch during stepping. For such case, the debugger will print a warning message when runtime is not matched in the DEBUG CONSOLE view.

[Eskibear]

Just FYI that the pattern could not cover some corner case (though we haven't figure out why), see adoptium/temurin-build#1610

[testforstephen]

Thanks for the info. I plan to reuse the JDT logic to get the Java version, where it uses release file under the Java home to get the version. I assume it's more stable regarding the jdt user base.

	public synchronized String readReleaseVersion(File javaHome) {

		String version = ""; //$NON-NLS-1$

		if (Files.notExists(Paths.get(javaHome.getAbsolutePath(), RELEASE_FILE))) {
			return version;
		}
		try (Stream<String> lines = Files.lines(Paths.get(javaHome.getAbsolutePath(), RELEASE_FILE), Charset.defaultCharset()).filter(s -> s.contains(JAVA_VERSION))) {
			Optional<String> hasVersion = lines.findFirst();
			if (hasVersion.isPresent()) {
				String line = hasVersion.get();
				version = line.substring(14, line.length() - 1); // length of JAVA_VERSION + 2 in JAVA_VERSION="9"
			}
		}
		catch (UncheckedIOException | IOException e) {
			LaunchingPlugin.log(e);
		}

		return version;

	}

[jdneo]

@CsCherrYY FYI

[Eskibear]

@testforstephen release file looks great! I tried several, one distribution of AdoptOpenJDK uses major version while others use full version. But it's the same value with java -version output.

Zulu:

IMPLEMENTOR="Azul Systems, Inc."
IMPLEMENTOR_VERSION="Zulu14.28+21-CA"
JAVA_VERSION="14.0.1"

Adopt:

IMPLEMENTOR="AdoptOpenJDK"
IMPLEMENTOR_VERSION="AdoptOpenJDK"
JAVA_VERSION="14"    // <-------------HERE

IMPLEMENTOR="AdoptOpenJDK"
IMPLEMENTOR_VERSION="AdoptOpenJDK"
JAVA_VERSION="13.0.2"

Oracle:

BUILD_TYPE="commercial"
IMPLEMENTOR="Oracle Corporation"
JAVA_VERSION="12.0.2"

[testforstephen]

YES. In real world, maybe 99% cases will contain release file. You could find the Java version from the release file first. If it doesn't exist, then fall back to java -version command.