FrameHelper uses default encoding of JVM instead of UTF-8

[smerschjohann]

Version

• vert.x core: 3.3.3
• vert.x tcp eventbus bridge: 3.3.3

Context

While implementing a Python Eventbus, I encountered that the message is encoded based on the file.encoding of the JVM instead of the wanted UTF-8.

I traced this down to the file FrameHelper.java which encodes the JSON document into a String on which getBytes() is called. Instead of this generic call, it should be exchanged by a getBytes("UTF-8") or similiar.

This problem mainly occures on windows as the default JVM environment is not set to UTF-8 by default.

Steps to reproduce

1. run JVM with -Dfile.encoding="iso-8859-15"
2. send data through message bus
3. check data transmitted on client side

Extra

• This problem can be eleminated by running the JVM using "-Dfile.encoding=UTF-8"