Enhance reflective pid-getting for Windows Java 8+

This is a modified version of a patch proposed in jruby#7515 (comment)
that uses a third mechanism for getting the PID: the `pid` method
added to ProcessImpl in 8 and made public in Process in 9.

For JRuby 10, which will target Java 17 or 21, we can just call
`pid` directly.

Fixes jruby#7515

core/src/main/java/org/jruby/util/ShellLauncher.java

@@ -42,6 +42,7 @@
 import java.io.PipedOutputStream;
 import java.io.PrintStream;
 import java.lang.reflect.Field;
+import java.lang.reflect.Method;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.util.ArrayList;
@@ -659,6 +660,7 @@ public static long getPidFromProcess(Process process) {
     private static final Field UNIXProcess_pid;
     private static final Class ProcessImpl;
     private static final Field ProcessImpl_handle;
+    private static final Method ProcessImpl_pid;
     private interface PidGetter { long getPid(Process process); }
     private static final PidGetter PID_GETTER;
 
@@ -681,7 +683,7 @@ private interface PidGetter { long getPid(Process process); }
         if (up != null) {
             try {
                 pid = up.getDeclaredField("pid");
-                Java.trySetAccessible(pid);
+                if (!Java.trySetAccessible(pid)) pid = null;
             } catch (NoSuchFieldException | SecurityException e) {
                 // ignore and try windows version
             }
@@ -694,69 +696,43 @@ private interface PidGetter { long getPid(Process process); }
         try {
             pi = Class.forName("java.lang.ProcessImpl");
             handle = pi.getDeclaredField("handle");
-            Java.trySetAccessible(handle);
+            if (!Java.trySetAccessible(handle)) {
+                handle = null;
+            }
         } catch (Exception e) {
             // ignore and use hashcode
         }
+
+        Method pi_pid = null;
+        if (pi != null) {
+            try {
+                pi_pid = pi.getMethod("pid");
+                if (!Java.trySetAccessible(pi_pid)) {
+                    pi_pid = null;
+                    if (handle == null) pi = null;
+                }
+            } catch (Exception e) {
+                // ignore and use hashcode
+            }
+        }
         ProcessImpl = pi;
         ProcessImpl_handle = handle;
+        ProcessImpl_pid = pi_pid;
 
         if (UNIXProcess_pid != null) {
             if (ProcessImpl_handle != null) {
                 // try both
-                pidGetter = new PidGetter() {
-                    public long getPid(Process process) {
-                        try {
-                            if (UNIXProcess.isInstance(process)) {
-                                return (Integer)UNIXProcess_pid.get(process);
-                            } else if (ProcessImpl.isInstance(process)) {
-                                Long hproc = (Long) ProcessImpl_handle.get(process);
-                                return WindowsFFI.getKernel32().GetProcessId(hproc);
-                            }
-                        } catch (Exception e) {
-                            // ignore and use hashcode
-                        }
-                        return process.hashCode();
-                    }
-                };
+                pidGetter = ShellLauncher::getPidBoth;
             } else {
                 // just unix
-                pidGetter = new PidGetter() {
-                    public long getPid(Process process) {
-                        try {
-                            if (UNIXProcess.isInstance(process)) {
-                                return (Integer)UNIXProcess_pid.get(process);
-                            }
-                        } catch (Exception e) {
-                            // ignore and use hashcode
-                        }
-                        return process.hashCode();
-                    }
-                };
+                pidGetter = ShellLauncher::getPidUnix;
             }
-        } else if (ProcessImpl_handle != null) {
+        } else if (ProcessImpl_handle != null || ProcessImpl_pid != null) {
             // just windows
-            pidGetter = new PidGetter() {
-                public long getPid(Process process) {
-                    try {
-                        if (ProcessImpl.isInstance(process)) {
-                            Long hproc = (Long) ProcessImpl_handle.get(process);
-                            return WindowsFFI.getKernel32().GetProcessId(hproc);
-                        }
-
-                    } catch (Exception e) {
-                        // ignore and use hashcode
-                    }
-                    return process.hashCode();
-                }
-            };
+            pidGetter = ShellLauncher::getPidWindows;
         } else {
             // neither - default PidGetter
-            pidGetter = new PidGetter() {
-                public long getPid(Process process) {
-                    return process.hashCode();
-                }
-            };
+            pidGetter = Object::hashCode;
         }
         PID_GETTER = pidGetter;
     }
@@ -765,6 +741,57 @@ public static long reflectPidFromProcess(Process process) {
         return PID_GETTER.getPid(process);
     }
 
+    private static long getPidBoth(Process process) {
+        try {
+            if (UNIXProcess.isInstance(process)) {
+                return getPidUnix(process);
+            } else if (ProcessImpl.isInstance(process)) {
+                return getPidWindows(process);
+            }
+        } catch (Exception e) {
+            // fall back on hashcode
+        }
+
+        return process.hashCode();
+    }
+
+    private static long getPidWindows(Process process) {
+        long pid = -1;
+        if (ProcessImpl_handle != null) {
+            try {
+                if (ProcessImpl.isInstance(process)) {
+                    Long hproc = (Long) ProcessImpl_handle.get(process);
+                    return WindowsFFI.getKernel32().GetProcessId(hproc);
+                }
+            } catch (Exception e) {
+                // fall back on pid logic
+            }
+        }
+
+        if (pid == -1 && ProcessImpl_pid != null) {
+            // JDK > 8 has a new way to look it up and also can't use "handle" field anymore
+            try {
+                return (long) ProcessImpl_pid.invoke(process);
+            } catch (Exception e2) {
+                // fall back on hashcode
+            }
+        }
+
+        return process.hashCode();
+    }
+
+    private static long getPidUnix(Process process) {
+        try {
+            if (UNIXProcess.isInstance(process)) {
+                return (Integer) UNIXProcess_pid.get(process);
+            }
+        } catch (Exception e) {
+            // fall back on hashcode
+        }
+
+        return process.hashCode();
+    }
+
     public static Process run(Ruby runtime, IRubyObject string) throws IOException {
         return run(runtime, new IRubyObject[] {string}, false);
     }