I don't know how to open the log for all the class. I set the enablelog to be true in the Http2Session and Http2Flusher manually. Below is the log.
2015-10-21 21:26:54.363:INFO::main: Logging initialized @159ms
2015-10-21 21:26:54.783:DBUG:oejh.HTTP2Session:qtp1360875712-15: Sending PrefaceFrame@245ca300
2015-10-21 21:26:54.784:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Appended PrefaceFrame@245ca300, frames=1
2015-10-21 21:26:54.784:DBUG:oejh.HTTP2Session:qtp1360875712-15: Sending SettingsFrame@3dae37f6,reply=false:{}
2015-10-21 21:26:54.784:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Appended SettingsFrame@3dae37f6,reply=false:{}, frames=2
2015-10-21 21:26:54.784:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Flushing HTTP2ClientSession@11abd39b{queueSize=2,sendWindow=65525,recvWindow=65525,streams=0,NOT_CLOSED}
2015-10-21 21:26:54.785:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Gathered for write PrefaceFrame@245ca300
2015-10-21 21:26:54.785:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Gathered for write SettingsFrame@3dae37f6,reply=false:{}
2015-10-21 21:26:54.785:DBUG:oejh.HTTP2Session:qtp1360875712-15: Generated PrefaceFrame@245ca300
2015-10-21 21:26:54.786:DBUG:oejh.HTTP2Session:qtp1360875712-15: Generated SettingsFrame@3dae37f6,reply=false:{}
2015-10-21 21:26:54.786:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Writing 2 buffers (33 bytes) for 2 frames [PrefaceFrame@245ca300, SettingsFrame@3dae37f6,reply=false:{}]
2015-10-21 21:26:54.788:DBUG:oejh.HTTP2Flusher:qtp1360875712-12: Written 2 frames for [PrefaceFrame@245ca300, SettingsFrame@3dae37f6,reply=false:{}]
2015-10-21 21:26:54.790:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Flushing HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=65525,recvWindow=65525,streams=0,NOT_CLOSED}
2015-10-21 21:26:54.790:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Flushed HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=65525,recvWindow=65525,streams=0,NOT_CLOSED}
2015-10-21 21:26:54.791:DBUG:oejh.HTTP2Session:qtp1360875712-15: Received SettingsFrame@73f89337,reply=false:{3=5, 4=2147483647, 5=16777215}
2015-10-21 21:26:54.792:DBUG:oejh.HTTP2Session:qtp1360875712-15: Update max local concurrent streams to 5
2015-10-21 21:26:54.792:DBUG:oejh.HTTP2Session:qtp1360875712-15: Update initial window size to 2147483647
2015-10-21 21:26:54.792:DBUG:oejh.HTTP2Session:qtp1360875712-15: Update max frame size to 16777215
2015-10-21 21:26:54.792:DBUG:oejh.HTTP2Session:qtp1360875712-15: Sending SettingsFrame@327d6aeb,reply=true:{}
2015-10-21 21:26:54.792:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Appended SettingsFrame@327d6aeb,reply=true:{}, frames=1
2015-10-21 21:26:54.793:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Flushing HTTP2ClientSession@11abd39b{queueSize=1,sendWindow=65525,recvWindow=65525,streams=0,NOT_CLOSED}
2015-10-21 21:26:54.793:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Gathered for write SettingsFrame@327d6aeb,reply=true:{}
2015-10-21 21:26:54.793:DBUG:oejh.HTTP2Session:qtp1360875712-15: Generated SettingsFrame@327d6aeb,reply=true:{}
2015-10-21 21:26:54.793:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Writing 1 buffers (9 bytes) for 1 frames [SettingsFrame@327d6aeb,reply=true:{}]
2015-10-21 21:26:54.794:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Written 1 frames for [SettingsFrame@327d6aeb,reply=true:{}]
2015-10-21 21:26:54.794:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Flushing HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=65525,recvWindow=65525,streams=0,NOT_CLOSED}
2015-10-21 21:26:54.794:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Flushed HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=65525,recvWindow=65525,streams=0,NOT_CLOSED}
2015-10-21 21:26:54.795:DBUG:oejh.HTTP2Session:qtp1360875712-15: Received WindowUpdateFrame@7e20fad5#0,delta=2147418112
2015-10-21 21:26:54.795:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Flushing HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=65525,recvWindow=65525,streams=0,NOT_CLOSED}
2015-10-21 21:26:54.796:DBUG:oejh.HTTP2Flusher:qtp1360875712-15: Flushed HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=2147483637,recvWindow=65525,streams=0,NOT_CLOSED}
2015-10-21 21:26:54.796:DBUG:oejh.HTTP2Session:qtp1360875712-15: Received SettingsFrame@31d8c981,reply=true:{}
2015-10-21 21:26:54.798:DBUG:oejh.HTTP2Session:main: Created local HTTP2Stream@6108b2d7#1{sendWindow=2147483647,recvWindow=65525,reset=false,NOT_CLOSED}
2015-10-21 21:26:54.799:DBUG:oejh.HTTP2Flusher:main: Appended HeadersFrame@1554909b#1{end=true}, frames=1
2015-10-21 21:26:54.799:DBUG:oejh.HTTP2Flusher:main: Flushing HTTP2ClientSession@11abd39b{queueSize=1,sendWindow=2147483637,recvWindow=65525,streams=1,NOT_CLOSED}
2015-10-21 21:26:54.799:DBUG:oejh.HTTP2Flusher:main: Gathered for write HeadersFrame@1554909b#1{end=true}
2015-10-21 21:26:54.809:DBUG:oejh.HTTP2Session:main: Generated HeadersFrame@1554909b#1{end=true}
2015-10-21 21:26:54.810:DBUG:oejh.HTTP2Flusher:main: Writing 2 buffers (69 bytes) for 1 frames [HeadersFrame@1554909b#1{end=true}]
2015-10-21 21:26:54.810:DBUG:oejh.HTTP2Flusher:main: Written 1 frames for [HeadersFrame@1554909b#1{end=true}]
2015-10-21 21:26:54.810:DBUG:oejh.HTTP2Flusher:main: Flushing HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=2147483637,recvWindow=65525,streams=1,NOT_CLOSED}
2015-10-21 21:26:54.810:DBUG:oejh.HTTP2Flusher:main: Flushed HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=2147483637,recvWindow=65525,streams=1,NOT_CLOSED}
2015-10-21 21:26:54.813:DBUG:oejh.HTTP2Session:qtp1360875712-13: Received DataFrame@3ed90f5#1{length:8038,end=false}
2015-10-21 21:26:54.814:DBUG:oejh.HTTP2Session:qtp1360875712-13: Received DataFrame@3a83903a#1{length:154,end=false}
DataFrame@3a83903a#1{length:154,end=false}index.html
2015-10-21 21:26:54.815:DBUG:oejh.HTTP2Session:qtp1360875712-13: Received DataFrame@7f6d0358#1{length:22,end=true}
2015-10-21 21:26:54.815:DBUG:oejh.HTTP2Session:qtp1360875712-13: Removed HTTP2Stream@6108b2d7#1{sendWindow=2147483647,recvWindow=57311,reset=false,CLOSED}
2015-10-21 21:27:04.818:DBUG:oejh.HTTP2Session:main: Sending GoAwayFrame@22f71333,0/
2015-10-21 21:27:04.819:DBUG:oejh.HTTP2Session:main: Sending GoAwayFrame@22f71333,0/
2015-10-21 21:27:04.819:DBUG:oejh.HTTP2Flusher:main: Appended GoAwayFrame@22f71333,0/, frames=1
2015-10-21 21:27:04.819:DBUG:oejh.HTTP2Flusher:main: Flushing HTTP2ClientSession@11abd39b{queueSize=1,sendWindow=2147483637,recvWindow=57311,streams=0,LOCALLY_CLOSED}
2015-10-21 21:27:04.820:DBUG:oejh.HTTP2Flusher:main: Gathered for write GoAwayFrame@22f71333,0/
2015-10-21 21:27:04.820:DBUG:oejh.HTTP2Session:main: Generated GoAwayFrame@22f71333,0/
2015-10-21 21:27:04.820:DBUG:oejh.HTTP2Flusher:main: Writing 1 buffers (17 bytes) for 1 frames [GoAwayFrame@22f71333,0/]
2015-10-21 21:27:04.821:DBUG:oejh.HTTP2Flusher:main: Written 1 frames for [GoAwayFrame@22f71333,0/]
2015-10-21 21:27:04.823:DBUG:oejh.HTTP2Flusher:main: Flushing HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=2147483637,recvWindow=57311,streams=0,LOCALLY_CLOSED}
2015-10-21 21:27:04.823:DBUG:oejh.HTTP2Flusher:main: Flushed HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=2147483637,recvWindow=57311,streams=0,LOCALLY_CLOSED}
2015-10-21 21:27:04.825:DBUG:oejh.HTTP2Session:qtp1360875712-10: Shutting down HTTP2ClientSession@11abd39b{queueSize=0,sendWindow=2147483637,recvWindow=57311,streams=0,LOCALLY_CLOSED}
DisconnectFrame@59830a39
2015-10-21 21:27:04.826:DBUG:oejh.HTTP2Session:qtp1360875712-10: Sending DisconnectFrame@59830a39
2015-10-21 21:27:04.826:DBUG:oejh.HTTP2Flusher:qtp1360875712-10: Appended DisconnectFrame@59830a39, frames=1
2015-10-21 21:27:04.826:DBUG:oejh.HTTP2Flusher:qtp1360875712-10: Flushing HTTP2ClientSession@11abd39b{queueSize=1,sendWindow=2147483637,recvWindow=57311,streams=0,LOCALLY_CLOSED}
2015-10-21 21:27:04.827:DBUG:oejh.HTTP2Flusher:qtp1360875712-10: Gathered for write DisconnectFrame@59830a39
2015-10-21 21:27:04.827:DBUG:oejh.HTTP2Session:qtp1360875712-10: Generated DisconnectFrame@59830a39
2015-10-21 21:27:04.827:DBUG:oejh.HTTP2Flusher:qtp1360875712-10: Writing 0 buffers (0 bytes) for 1 frames [DisconnectFrame@59830a39]
2015-10-21 21:27:04.827:DBUG:oejh.HTTP2Flusher:qtp1360875712-10: Failed