Fix UTF8Writer problem, similar to #70

Author: cowtowncoder

src/main/java/com/fasterxml/jackson/dataformat/yaml/UTF8Writer.java

@@ -44,6 +44,8 @@ public UTF8Writer(OutputStream out)
         byte[] buffer = _bufferHolder[0];
         if (buffer == null) {
             _bufferHolder[0] = buffer = new byte[DEFAULT_BUFFER_SIZE];
+        } else {
+            _bufferHolder[0] = null;
         }
         _outBuffer = buffer;
         /* Max. expansion for a single char (in unmodified UTF-8) is
@@ -69,16 +71,14 @@ private static byte[][] _findBufferHolder()
     }
 
     @Override
-    public Writer append(char c)
-        throws IOException
+    public Writer append(char c) throws IOException
     {
         write(c);
         return this;
     }
 
     @Override
-    public void close()
-        throws IOException
+    public void close() throws IOException
     {
         if (_out != null) {
             if (_outPtr > 0) {
@@ -88,10 +88,12 @@ public void close()
             OutputStream out = _out;
             _out = null;
 
-            byte[] buf = _outBuffer;
-            if (buf != null) {
-                _outBuffer = null;
-                _bufferHolder[0] = buf;
+            if (_bufferHolder != null) {
+                byte[] buf = _outBuffer;
+                if (buf != null) {
+                    _outBuffer = null;
+                    _bufferHolder[0] = buf;
+                }
             }
             out.close();
 
@@ -107,8 +109,7 @@ public void close()
     }
 
     @Override
-    public void flush()
-        throws IOException
+    public void flush() throws IOException
     {
         if (_out != null) {
             if (_outPtr > 0) {
@@ -120,15 +121,13 @@ public void flush()
     }
 
     @Override
-    public void write(char[] cbuf)
-        throws IOException
+    public void write(char[] cbuf) throws IOException
     {
         write(cbuf, 0, cbuf.length);
     }
 
     @Override
-    public void write(char[] cbuf, int off, int len)
-        throws IOException
+    public void write(char[] cbuf, int off, int len) throws IOException
     {
         if (len < 2) {
             if (len == 1) {
@@ -276,7 +275,7 @@ public void write(String str) throws IOException
     }
 
     @Override
-    public void write(String str, int off, int len)  throws IOException
+    public void write(String str, int off, int len) throws IOException
     {
         if (len < 2) {
             if (len == 1) {

src/test/java/com/fasterxml/jackson/dataformat/yaml/ExceptionConversionTest.java

@@ -19,7 +19,8 @@ public void testSimpleParsingLeakage() throws Exception
         } catch (org.yaml.snakeyaml.scanner.ScannerException e) {
             fail("Internal exception type: "+e);
         } catch (JsonMappingException e) {
-            e.printStackTrace();
+//            e.printStackTrace();
+            verifyException(e, "YAML decoding problem");
             // good
         } catch (Exception e) {
             fail("Unknown exception: "+e);