6903354: deadlock involving Component.show & SunToolkit.getImageFromHash

Reviewed-by: art, bae

src/share/classes/sun/awt/SunToolkit.java

@@ -800,9 +800,9 @@ public abstract class SunToolkit extends Toolkit
     }
 
 
-    static SoftCache imgCache = new SoftCache();
+    static final SoftCache imgCache = new SoftCache();
 
-    static synchronized Image getImageFromHash(Toolkit tk, URL url) {
+    static Image getImageFromHash(Toolkit tk, URL url) {
         SecurityManager sm = System.getSecurityManager();
         if (sm != null) {
             try {
@@ -830,6 +830,7 @@ public abstract class SunToolkit extends Toolkit
                     sm.checkConnect(url.getHost(), url.getPort());
             }
         }
+        synchronized (imgCache) {
             Image img = (Image)imgCache.get(url);
             if (img == null) {
                 try {
@@ -840,13 +841,15 @@ public abstract class SunToolkit extends Toolkit
             }
             return img;
         }
+    }
 
-    static synchronized Image getImageFromHash(Toolkit tk,
+    static Image getImageFromHash(Toolkit tk,
                                                String filename) {
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkRead(filename);
         }
+        synchronized (imgCache) {
             Image img = (Image)imgCache.get(filename);
             if (img == null) {
                 try {
@@ -857,6 +860,7 @@ public abstract class SunToolkit extends Toolkit
             }
             return img;
         }
+    }
 
     public Image getImage(String filename) {
         return getImageFromHash(this, filename);