--- old/src/share/classes/com/sun/tools/sjavac/comp/PubapiVisitor.java	2014-08-09 00:28:48.967821782 +0200
+++ new/src/share/classes/com/sun/tools/sjavac/comp/PubapiVisitor.java	2014-08-09 00:28:48.847825264 +0200
@@ -25,8 +25,11 @@
 
 package com.sun.tools.sjavac.comp;
 
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import java.util.LinkedList;
 import javax.lang.model.element.Modifier;
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.TypeElement;
@@ -44,17 +47,46 @@
  */
 public class PubapiVisitor extends ElementScanner9<Void, Void> {
 
-    StringBuffer sb;
-    // Important that it is 1! Part of protocol over wire, silly yes.
-    // Fix please.
-    int indent = 1;
+    // The pubapi is stored here.
+    List<String> api = new LinkedList<String>();
+    // The hash of the pubapi (excluding paths to jars/classes and their timestamp)
+    int hash;
+    // Indentation level.
+    int indent = 0;
+    // The class location info is for example:
+    // ZipFileIndexFileObject[/home/fredrik/bin/jdk1.8.0/lib/tools.jar(com/sun/tools/javac/comp/Resolve.class) 1396702502000
+    // ie the jfileobj.toString() + " " + jfileobj.getLastModified()
+    String class_loc_info = "";
+
+    // If true, then store full public api information, not just the hash.
+    // Makes it much easier to debug any public api bugs.
+    boolean debugPubapi = false;
 
-    public PubapiVisitor(StringBuffer sb) {
-        this.sb = sb;
+    String depth(int l) {
+        return "________________________________".substring(0, l);
     }
 
-    String depth(int l) {
-        return "                                              ".substring(0, l);
+    public void classLocInfo(String s) {
+        class_loc_info = " "+s;
+    }
+
+    public void construct(TypeElement e) {
+        visit(e);
+        hash = 0;
+        List<String> sorted_api = new ArrayList<>();
+        sorted_api.addAll(api);
+        // Why sort here? Because we want the same pubapi hash to be generated
+        // for both a source compile and a classpath extraction.
+        Collections.sort(sorted_api);
+
+        for (String s : sorted_api) {
+            hash ^= s.hashCode();
+        }
+        api = new LinkedList<String>();
+        api.add(0, "PUBAPI "+e.getQualifiedName()+" "+Integer.toString(Math.abs(hash),16)+class_loc_info);
+        if (debugPubapi) {
+            api.addAll(sorted_api);
+        }
     }
 
     @Override
@@ -62,7 +94,7 @@
         if (e.getModifiers().contains(Modifier.PUBLIC)
             || e.getModifiers().contains(Modifier.PROTECTED))
         {
-            sb.append(depth(indent) + "TYPE " + e.getQualifiedName() + "\n");
+            api.add(depth(indent) + "!TYPE " + e.getQualifiedName());
             indent += 2;
             Void v = super.visitType(e, p);
             indent -= 2;
@@ -75,8 +107,7 @@
     public Void visitVariable(VariableElement e, Void p) {
         if (e.getModifiers().contains(Modifier.PUBLIC)
             || e.getModifiers().contains(Modifier.PROTECTED)) {
-            sb.append(depth(indent)).append("VAR ")
-                    .append(makeVariableString(e)).append("\n");
+            api.add(depth(indent)+"VAR "+makeVariableString(e));
         }
         // Safe to not recurse here, because the only thing
         // to visit here is the constructor of a variable declaration.
@@ -90,8 +121,7 @@
     public Void visitExecutable(ExecutableElement e, Void p) {
         if (e.getModifiers().contains(Modifier.PUBLIC)
             || e.getModifiers().contains(Modifier.PROTECTED)) {
-            sb.append(depth(indent)).append("METHOD ")
-                    .append(makeMethodString(e)).append("\n");
+            api.add(depth(indent)+"METHOD "+makeMethodString(e));
         }
         return null;
     }