incorrect buffer filling and false EOF

When reading the following graph.txt (originally .json), I get the following error:

com.google.gson.JsonSyntaxException: java.io.EOFException: End of input at line 1 column 1025 path $.edges[3].weight
                      at com.google.gson.Gson.fromJson(Gson.java:898)
                      at com.google.gson.Gson.fromJson(Gson.java:853)
                      at com.google.gson.Gson.fromJson(Gson.java:802)

When I went down the rabbit hole I discovered that on java.lang.Thread.State: RUNNABLE at com.google.gson.stream.JsonReader.peek(JsonReader.java:453), when p=16, instead of returning with JsonToken.NUMBER, it continued to the next case and returned JsonToken.END_DOCUMENT.

For your convenience, I’ve attached dump from before and after the bug (col 1023,1024 and col 1025), and when I went WTF???. Gson just before crush (1023).txt Gson just before crush (1024).txt Gson just after crush (1025).txt Gson WTF - should have returned.txt

If you need, the following code was used (.java was replaced with .java.txt to get around GitHub exclusions):

•       Gson gson = new Gson();
        InputStream is = getResources().openRawResource(R.raw.graph);
        String json = (new Scanner(is)).useDelimiter("\\Z").next();
        WeightedGraph<LocationDataPoint> TestGraph = gson.fromJson(json, new TypeToken<WeightedGraph<LocationDataPoint>>(){}.getType()); ```
  

• LocationDataPoint.java.txt
• WeightedGraph.java.txt
• Vertex.java.txt
• Graph.java.txt
• Edge.java.txt

The graph.json was created by Gson, so it should be compatible with Gson…

graph.txt

[trusitshah]

I got a similar issue in my android app.

Caused by com.google.gson.JsonSyntaxException: java.io.EOFException: End of input at line 1 column 225931 path $.data.polygons[220].paths[14].lat at com.google.gson.Gson.fromJson(Gson.java:898) at com.google.gson.Gson.fromJson(Gson.java:853) at com.google.gson.Gson.fromJson(Gson.java:802) at com.google.gson.Gson.fromJson(Gson.java:774)

[Marcono1234]

This error can be avoided by passing InputStreamReader as a parameter to the fromJson method. In my case this error was caused by some lack of memory problems on some devices and the reader’s stream reaches its end before the actual end of your json.

That is actually a good point; the documentation for Scanner says:

If an invocation of the underlying readable’s Readable.read(CharBuffer) method throws an IOException then the scanner assumes that the end of the input has been reached. The most recent IOException thrown by the underlying readable can be retrieved via the ioException() method.

So it could indeed be the case that the underlying stream threw an exception and Scanner silently considered it as end of stream. In case anyone is still experiencing this, could you please make sure you experience this even without using Scanner? Please also try the latest Gson version.