fix: handle NoSuchMethodError for isMainMethodCandidate() on older JDT Core

Catch NoSuchMethodError when calling SourceMethod.isMainMethodCandidate()
in ResolveMainClassHandler and ResolveMainMethodHandler. This method was
added in JDT Core 3.36 and is unavailable on older versions, causing
the debugger to fail entirely when resolving main classes.

Fixes microsoft/vscode-java-debug#1598

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: wenytang-ms

com.microsoft.java.debug.plugin/src/main/java/com/microsoft/java/debug/plugin/internal/ResolveMainClassHandler.java

@@ -241,6 +241,13 @@ private boolean isMainMethod(IMethod method) {
             return method.isMainMethod();
         } catch (JavaModelException e) {
             // do nothing
+        } catch (NoSuchMethodError e) {
+            // isMainMethodCandidate() was added in JDT Core 3.36, fall back to isMainMethod()
+            try {
+                return method.isMainMethod();
+            } catch (JavaModelException ex) {
+                // do nothing
+            }
         }
 
         return false;

com.microsoft.java.debug.plugin/src/main/java/com/microsoft/java/debug/plugin/internal/ResolveMainMethodHandler.java

@@ -112,9 +112,13 @@ public static IMethod getMainMethod(IType type) throws JavaModelException {
         boolean allowInstanceMethod = isInstanceMainMethodSupported(type);
         List<IMethod> methods = new ArrayList<>();
         for (IMethod method : type.getMethods()) {
-            if (method instanceof SourceMethod
-                && ((SourceMethod) method).isMainMethodCandidate()) {
-                methods.add(method);
+            try {
+                if (method instanceof SourceMethod
+                    && ((SourceMethod) method).isMainMethodCandidate()) {
+                    methods.add(method);
+                }
+            } catch (NoSuchMethodError e) {
+                // isMainMethodCandidate() was added in JDT Core 3.36, skip if unavailable
             }
 
             if (method.isMainMethod()) {