Fixing parsing of unquoted strings to be (somewhat) consistent with previous versions of Gson. The difference with this version is that Gson will throw a more specific exception rather than JsonParseException.

gson/src/main/java/com/google/gson/Gson.java

@@ -17,7 +17,10 @@
 package com.google.gson;
 
 import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonToken;
 import com.google.gson.stream.JsonWriter;
+import com.google.gson.stream.MalformedJsonException;
+
 import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
@@ -452,7 +455,9 @@ public final class Gson {
    * @since 1.2
    */
   public <T> T fromJson(Reader json, Class<T> classOfT) throws JsonSyntaxException, JsonIOException {
-    Object object = fromJson(new JsonReader(json), classOfT);
+    JsonReader jsonReader = new JsonReader(json);
+    Object object = fromJson(jsonReader, classOfT);
+    assertFullConsumption(object, jsonReader);
     return Primitives.wrap(classOfT).cast(object);
   }
 
@@ -476,7 +481,22 @@ public final class Gson {
    * @since 1.2
    */
   public <T> T fromJson(Reader json, Type typeOfT) throws JsonIOException, JsonSyntaxException {
-    return this.<T>fromJson(new JsonReader(json), typeOfT);
+    JsonReader jsonReader = new JsonReader(json);
+    T object = fromJson(jsonReader, typeOfT);
+    assertFullConsumption(object, jsonReader);
+    return object;
+  }
+
+  private static void assertFullConsumption(Object obj, JsonReader reader) {
+    try {
+      if (obj != null && reader.peek() != JsonToken.END_DOCUMENT) {
+        throw new JsonIOException("JSON document was not fully consumed.");
+      }
+    } catch (MalformedJsonException e) {
+      throw new JsonSyntaxException(e);
+    } catch (IOException e) {
+      throw new JsonIOException(e);
+    }
   }
 
   /**

gson/src/main/java/com/google/gson/JsonParser.java

@@ -16,7 +16,11 @@
 package com.google.gson;
 
 import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonToken;
+import com.google.gson.stream.MalformedJsonException;
+
 import java.io.EOFException;
+import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
 
@@ -50,7 +54,20 @@ public final class JsonParser {
    * @since 1.3
    */
   public JsonElement parse(Reader json) throws JsonIOException, JsonSyntaxException {
-    return parse(new JsonReader(json));
+    try {
+      JsonReader jsonReader = new JsonReader(json);
+      JsonElement element = parse(jsonReader);
+      if (!element.isJsonNull() && jsonReader.peek() != JsonToken.END_DOCUMENT) {
+        throw new JsonSyntaxException("Did not consume the entire document.");
+      }
+      return element;
+    } catch (MalformedJsonException e) {
+      throw new JsonSyntaxException(e);
+    } catch (IOException e) {
+      throw new JsonIOException(e);
+    } catch (NumberFormatException e) {
+      throw new JsonSyntaxException(e);
+    }
   }
 
   /**

gson/src/test/java/com/google/gson/JsonParserTest.java

@@ -18,10 +18,12 @@ package com.google.gson;
 
 import com.google.gson.common.TestTypes.BagOfPrimitives;
 import com.google.gson.stream.JsonReader;
+
+import junit.framework.TestCase;
+
 import java.io.CharArrayReader;
 import java.io.CharArrayWriter;
 import java.io.StringReader;
-import junit.framework.TestCase;
 
 /**
  * Unit test for {@link JsonParser}
@@ -29,7 +31,6 @@ import junit.framework.TestCase;
  * @author Inderjeet Singh
  */
 public class JsonParserTest extends TestCase {
-  
   private JsonParser parser;
 
   @Override
@@ -57,6 +58,14 @@ public class JsonParserTest extends TestCase {
     assertTrue(e.isJsonNull());
   }
 
+  public void testParseUnquotedStringSentence() {
+    String unquotedSentence = "Test is a test..blah blah";
+    try {
+      parser.parse(unquotedSentence);
+      fail();
+    } catch (JsonSyntaxException expected) { }
+  }
+
   public void testParseMixedArray() {
     String json = "[{},13,\"stringValue\"]";
     JsonElement e = parser.parse(json);

gson/src/test/java/com/google/gson/functional/PrimitiveTest.java

@@ -16,15 +16,20 @@
 
 package com.google.gson.functional;
 
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.JsonSyntaxException;
+import com.google.gson.LongSerializationPolicy;
+import com.google.gson.common.TestTypes.CrazyLongTypeAdapter;
+
+import junit.framework.TestCase;
+
 import java.io.StringReader;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 
-import com.google.gson.*;
-import junit.framework.TestCase;
-
-import com.google.gson.common.TestTypes.CrazyLongTypeAdapter;
-
 /**
  * Functional tests for Json primitive values: integers, and floating point numbers.
  *
@@ -557,6 +562,23 @@ public class PrimitiveTest extends TestCase {
     assertEquals(25, value);
   }
 
+  public void testQuotedStringSerializationAndDeserialization() throws Exception {
+    String value = "String Blah Blah Blah...1, 2, 3";
+    String serializedForm = gson.toJson(value);
+    assertEquals("\"" + value + "\"", serializedForm);
+
+    String actual = gson.fromJson(serializedForm, String.class);
+    assertEquals(value, actual);
+  }
+
+  public void testUnquotedStringDeserialization() throws Exception {
+    String value = "String Blah Blah Blah...1, 2, 3";
+    try {
+      gson.fromJson(value, String.class);
+      fail();
+    } catch (JsonSyntaxException expected) { }
+  }
+
   public void testHtmlCharacterSerialization() throws Exception {
     String target = "<script>var a = 12;</script>";
     String result = gson.toJson(target);