How to find the reason for a jetty 400 error? - jetty

Question

I have a jetty server (version 9.4.11. It is used in combination with org.restlet-2.4.3). A client is sending a POST message to an api on my server (route "/pos/v1/purchasable_items") and jetty responds with 400 code. I cannot figure out the reason. I would really appreciate some help.
Here is the full log of jetty:
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Queued change org.eclipse.jetty.io.ManagedSelector$Accept#616b6a22 on org.eclipse.jetty.io.ManagedSelector#79c26be5 id=1 keys=0 selected=0 updates=0
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - wakeup on submit org.eclipse.jetty.io.ManagedSelector#79c26be5 id=1 keys=0 selected=0 updates=1
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e woken with none selected
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e woken up from select, 0/0/0 selected
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e processing 0 keys, 1 updates
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - updateable 1
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - update org.eclipse.jetty.io.ManagedSelector$Accept#616b6a22
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.util.thread.QueuedThreadPool - queue org.eclipse.jetty.io.ManagedSelector$Accept#616b6a22
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - updates 0
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e waiting with 1 keys
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.util.thread.QueuedThreadPool - run org.eclipse.jetty.io.ManagedSelector$Accept#616b6a22
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.IdleTimeout - SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=8/100000}{io=0/0,kio=0,kro=0}-><null> idle timeout check, elapsed: 7 ms, remaining: 99993 ms
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.PreEncodedHttpField - HttpField encoders loaded: [org.eclipse.jetty.http.Http1FieldPreEncoder#1525e6cb]
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpChannel - new HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0} -> SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=72/100000}{io=0/0,kio=0,kro=0}-><null>,null,HttpChannelState#7ae84ea1{s=IDLE a=NOT_ASYNC i=true r=IDLE w=false}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - New HTTP Connection HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=80/100000}{io=0/0,kio=0,kro=0}-><null>
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.AbstractEndPoint - onOpen SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=81/100000}{io=0/0,kio=0,kro=0}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.AbstractConnection - onOpen HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=81/100000}{io=0/0,kio=0,kro=0}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.AbstractConnection - fillInterested HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=81/100000}{io=0/0,kio=0,kro=0}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.FillInterest - interested FillInterest#72454313{AC.ReadCB#30023a7c{HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=0/100000}{io=0/0,kio=0,kro=0}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}}}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ChannelEndPoint - changeInterests p=false 0->1 for SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=0/100000}{io=0/1,kio=0,kro=0}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Queued change org.eclipse.jetty.io.ChannelEndPoint$1#528ccae5 on org.eclipse.jetty.io.ManagedSelector#79c26be5 id=1 keys=1 selected=0 updates=0
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - wakeup on submit org.eclipse.jetty.io.ManagedSelector#79c26be5 id=1 keys=1 selected=0 updates=1
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e woken with none selected
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e woken up from select, 0/0/1 selected
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e processing 0 keys, 1 updates
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - updateable 1
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - update org.eclipse.jetty.io.ChannelEndPoint$1#528ccae5
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Created SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=0/100000}{io=0/1,kio=0,kro=0}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.util.thread.QueuedThreadPool - ran org.eclipse.jetty.io.ManagedSelector$Accept#616b6a22
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ChannelEndPoint - Key interests updated 0 -> 1 on SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=1/100000}{io=1/1,kio=1,kro=0}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - updates 0
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e waiting with 1 keys
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e woken up from select, 1/1/1 selected
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e processing 1 keys, 0 updates
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - selected 1 channel=java.nio.channels.SocketChannel[connected local=/127.0.0.1:8182 remote=/127.0.0.1:50589], selector=sun.nio.ch.WindowsSelectorImpl#5c1f2b6e, interestOps=1, readyOps=1 SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=1/100000}{io=1/1,kio=1,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ChannelEndPoint - onSelected 1->0 r=true w=false for SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=1/100000}{io=1/0,kio=1,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ChannelEndPoint - task CEP:SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=1/100000}{io=1/0,kio=1,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}:runFillable:BLOCKING
12:56:05 [36mDEBUG[0;39m o.eclipse.jetty.util.thread.ReservedThreadExecutor - ReservedThreadExecutor#77a9ea73{s=0/8,p=0} tryExecute EatWhatYouKill#218cf600/SelectorProducer#4aecb548/PRODUCING/p=false/QueuedThreadPool[qtp103099676]#6252d1c{STARTED,8<=8<=300,i=3,q=0}[ReservedThreadExecutor#77a9ea73{s=0/8,p=0}][pc=0,pic=0,pec=0,epc=0]#2021-06-17T12:56:05.8701778+02:00
12:56:05 [36mDEBUG[0;39m o.eclipse.jetty.util.thread.ReservedThreadExecutor - ReservedThreadExecutor#77a9ea73{s=0/8,p=1} startReservedThread p=1
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.util.thread.QueuedThreadPool - queue ReservedThreadExecutor#77a9ea73{s=0/8,p=1}#73ca3be9
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.util.thread.QueuedThreadPool - run ReservedThreadExecutor#77a9ea73{s=0/8,p=1}#73ca3be9
12:56:05 [36mDEBUG[0;39m o.eclipse.jetty.util.thread.ReservedThreadExecutor - ReservedThreadExecutor#77a9ea73{s=1/8,p=1}#73ca3be9 started
12:56:05 [36mDEBUG[0;39m o.e.jetty.util.thread.strategy.EatWhatYouKill - EatWhatYouKill#218cf600/SelectorProducer#4aecb548/PRODUCING/p=false/QueuedThreadPool[qtp103099676]#6252d1c{STARTED,8<=8<=300,i=2,q=0}[ReservedThreadExecutor#77a9ea73{s=0/8,p=1}][pc=0,pic=0,pec=0,epc=0]#2021-06-17T12:56:05.8721778+02:00 m=PRODUCE_EXECUTE_CONSUME t=CEP:SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=3/100000}{io=1/0,kio=1,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}:runFillable:BLOCKING/BLOCKING
12:56:05 [36mDEBUG[0;39m o.eclipse.jetty.util.thread.ReservedThreadExecutor - ReservedThreadExecutor#77a9ea73{s=1/8,p=0}#73ca3be9 waiting
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.util.thread.QueuedThreadPool - queue CEP:SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=3/100000}{io=1/0,kio=1,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}:runFillable:BLOCKING
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - updateable 0
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - updates 0
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ChannelEndPoint - Key interests updated 1 -> 0 on SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=3/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ManagedSelector - Selector sun.nio.ch.WindowsSelectorImpl#5c1f2b6e waiting with 1 keys
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.util.thread.QueuedThreadPool - run CEP:SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=3/100000}{io=0/0,kio=1,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}:runFillable:BLOCKING
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.FillInterest - fillable FillInterest#72454313{AC.ReadCB#30023a7c{HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=FI,flush=-,to=4/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}}}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=4/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0} onFillable enter HttpChannelState#7ae84ea1{s=IDLE a=NOT_ASYNC i=true r=IDLE w=false} null
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ChannelEndPoint - filled 181 SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=6/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=3/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0} filled 181 HeapByteBuffer#25fdf14c[p=0,l=181,c=8192,r=181]={<<<POST /pos/v1/purc...00-continue\r\n\r\n>>>\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00...\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=3/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=START,0 of -1},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=0,c=false,a=IDLE,uri=null,age=0} parse HeapByteBuffer#25fdf14c[p=0,l=181,c=8192,r=181]={<<<POST /pos/v1/purc...00-continue\r\n\r\n>>>\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00...\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00} {}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - parseNext s=START HeapByteBuffer#25fdf14c[p=0,l=181,c=8192,r=181]={<<<POST /pos/v1/purc...00-continue\r\n\r\n>>>\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00...\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - START --> SPACE1
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - SPACE1 --> URI
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - URI --> SPACE2
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - SPACE2 --> REQUEST_VERSION
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - REQUEST_VERSION --> HEADER
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Content-Type: application/x-www-form-urlencoded --> IN_VALUE
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Content-Type: application/x-www-form-urlencoded --> FIELD
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Host --> VALUE
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Host --> IN_VALUE
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Host --> FIELD
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Content-Length --> VALUE
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Content-Length --> IN_VALUE
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Content-Length --> FIELD
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Expect --> VALUE
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Expect --> IN_VALUE
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER:Expect --> FIELD
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - HEADER --> CONTENT
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpChannel - REQUEST for //127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05 on HttpChannelOverHttp#3b503229{r=1,c=false,a=IDLE,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=1}
POST //127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05 HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Host: 127.0.0.1:8182
Content-Length: 228
Expect: 100-continue
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=IDLE,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=2}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=13/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=IDLE,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=2} parsed true HttpParser{s=CONTENT,0 of 228}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - releaseRequestBuffer HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=IDLE,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=2}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=13/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=IDLE,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=2}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpChannel - HttpChannelOverHttp#3b503229{r=1,c=false,a=IDLE,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=3} handle //127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpChannelState - handling HttpChannelState#7ae84ea1{s=IDLE a=NOT_ASYNC i=true r=IDLE w=false}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpChannel - HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=4} action DISPATCH
12:56:05 [36mTRACE[0;39m org.restlet.Component.ServerRouter - Call score for the "org.restlet.routing.VirtualHost#24386839" host: 1.0
12:56:05 [36mDEBUG[0;39m org.restlet.Component.ServerRouter - Default virtual host selected
12:56:05 [36mDEBUG[0;39m org.restlet.Component.ServerRouter - Base URI: "http://127.0.0.1:8182". Remaining part: "/pos/v1/purchasable_items?d=17.06.2021%2012:56:05"
12:56:05 [36mTRACE[0;39m org.restlet.VirtualHost - Call score for the "" URI pattern: 0.5
12:56:05 [36mDEBUG[0;39m org.restlet.VirtualHost - Selected route: "" -> de.sage.scheduler.access.server.AccessServerImpl#440e3ce6
12:56:05 [36mTRACE[0;39m org.restlet.VirtualHost - No characters were matched
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ChannelEndPoint - filled 0 SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=47/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=36}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ChannelEndPoint - filled 0 SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=47/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=36}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=36}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=47/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=36} filled 0 HeapByteBuffer#25fdf14c[p=0,l=0,c=8192,r=0]={<<<>>>POST /pos/v1/purc...\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=36}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=48/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=37} parse HeapByteBuffer#25fdf14c[p=0,l=0,c=8192,r=0]={<<<>>>POST /pos/v1/purc...\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00} {}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.http.HttpParser - parseNext s=CONTENT HeapByteBuffer#25fdf14c[p=0,l=0,c=8192,r=0]={<<<>>>POST /pos/v1/purc...\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=37}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=48/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=37} parsed false HttpParser{s=CONTENT,0 of 228}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - releaseRequestBuffer HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=37}<-SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=-,to=48/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=START}]=>HttpChannelOverHttp#3b503229{r=1,c=false,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=37}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpChannel - sendResponse info=HTTP/1.1{s=100,h=-1,cl=-1} content=null complete=false committing=true callback=Blocker#5a2856fc{null}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpChannel - COMMIT for /pos/v1/purchasable_items on HttpChannelOverHttp#3b503229{r=1,c=true,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=37}
100 null HTTP/1.1
null
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - org.eclipse.jetty.server.HttpConnection$SendCallback#364501c7[PROCESSING][i=HTTP/1.1{s=100,h=-1,cl=-1},cb=org.eclipse.jetty.server.HttpChannel$Commit100Callback#d25f545] generate: NEED_HEADER (null,null,false)#START
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - org.eclipse.jetty.server.HttpConnection$SendCallback#364501c7[PROCESSING][i=HTTP/1.1{s=100,h=-1,cl=-1},cb=org.eclipse.jetty.server.HttpChannel$Commit100Callback#d25f545] generate: FLUSH ([p=0,l=25,c=8192,r=25],null,false)#COMPLETING_1XX
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.WriteFlusher - write: WriteFlusher#786527a2{IDLE}->null [HeapByteBuffer#25fdf14c[p=0,l=25,c=8192,r=25]={<<<HTTP/1.1 100 Continue\r\n\r\n>>>items?d=17.06.202...\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00}]
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.WriteFlusher - update WriteFlusher#786527a2{WRITING}->null:IDLE-->WRITING
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.ChannelEndPoint - flushed 25 SocketChannelEndPoint#54fedde4{/127.0.0.1:50589<->/127.0.0.1:8182,OPEN,fill=-,flush=W,to=55/100000}{io=0/0,kio=0,kro=1}->HttpConnection#30023a7c[p=HttpParser{s=CONTENT,0 of 228},g=HttpGenerator#7f9bfe40{s=COMPLETING_1XX}]=>HttpChannelOverHttp#3b503229{r=1,c=true,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=44}
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.WriteFlusher - Flushed=true written=25 remaining=0 WriteFlusher#786527a2{WRITING}->null
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.io.WriteFlusher - update WriteFlusher#786527a2{IDLE}->null:WRITING-->IDLE
12:56:05 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpConnection - org.eclipse.jetty.server.HttpConnection$SendCallback#364501c7[PROCESSING][i=HTTP/1.1{s=100,h=-1,cl=-1},cb=org.eclipse.jetty.server.HttpChannel$Commit100Callback#d25f545] generate: DONE ([p=25,l=25,c=8192,r=0],null,false)#START
12:56:09 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpChannel - sendResponse info=null content=DirectByteBuffer#3b173fda[p=0,l=84,c=32768,r=84]={<<<{"DESC":"The requ...formed syntax"}>>>\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00...\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00} complete=false committing=true callback=Blocker#5a2856fc{null}
12:56:09 [36mDEBUG[0;39m org.eclipse.jetty.server.HttpChannel - COMMIT for /pos/v1/purchasable_items on HttpChannelOverHttp#3b503229{r=1,c=true,a=DISPATCHED,uri=//127.0.0.1:8182/pos/v1/purchasable_items?d=17.06.2021%2012:56:05,age=3888}
400 null HTTP/1.1
Content-Type: application/json;charset=utf-8
Date: Thu, 17 Jun 2021 10:56:09 GMT
Accept-Ranges: bytes
Server: Restlet-Framework/2.4.3
Access-Control-Allow-Credentials: true
Access-Control-Allow-Headers: Authorization, Content-Type
Access-Control-Allow-Methods: DELETE, POST, GET, OPTIONS, PUT
I have also tried to debug it with Wireshark without any success. This is the overview of the communication (Port 8182 im by server):
This is the POST request in detail from Wireshark:
I would be happy about anyone giving me a hint.

Answer 1

Your client is sending a POST with an Expect: 100-Continue header (a normal enough concept).
It's a bit hard to tell from your wireshark, but it looks like your client isn't handling the HTTP/1.1 100 Continue response properly.
Your client should wait on sending the body of the request until it receives the HTTP/1.1 100 Continue response.
And when it sends the request body, it should only contain the request body, it should not send the request headers again. (which your logs on jetty, and your wireshark both seem to show).
These headers do not conform to the Content-Type: application/x-www-form-urlencoded and result in a 400 Bad Request response.
Advice, Upgrade both your Restlet version, and your Jetty version.
Judging by the headers sent on the request, you have a very old version of restlet (there are some headers that i'm expecting to see, but do not).
Your Jetty version 9.4.11 is quite old and is missing many important fixes (one of which is more clear error messages around 400 Bad Request, which would have helped you figure this out yourself). You are 3,081 updates (yes, three thousand eighty one updates) behind version 9.4.42.v20210604.

Answer 2

The problem turned out to be a user-agent black list which blocked the request because it had no user-agent. It had nothing to do with jetty.