Hi, we are using tomcat 8.0.30 without problems.
I have tested upgrade to 8.0.38 today and I got this error More env. details JDK 8, tested on both Linux and Windows using different JDK 8 updates (71, 111). 15-Nov-2016 17:14:51.189 INFO [http-nio-8080-exec-2] org.apache.coyote.http11.AbstractHttp11Processor.process Error parsing HTTP request header Note: further occurrences of HTTP header parsing errors will be logged at DEBUG level. java.lang.IllegalArgumentException: Invalid character found in the request target. The valid characters are defined in RFC 7230 and RFC 3986 at org.apache.coyote.http11.AbstractNioInputBuffer.parseRequestLine(AbstractNioInputBuffer.java:283) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1017) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745) The parameter in the request is this /list?criteria={%22$type%22:%22Equal%22,%22attr%22:%22id%22,%22value%22:101} Looks like this commit caused the exception https://github.com/apache/tomcat80/commit/779d5d34e68e50d2f721897050b147106992f566 The commit message says: Add additional checks for valid characters to the HTTP request line parsing so invalid request lines are rejected sooner. We don't get any error in 8.0.30 using same request. The state in 8.0.30 was bug or 8.0.38 should process parameter criteria={%22$type%22:%22Equal%22,%22attr%22:%22id%22,%22value%22:101} ? Thanks. Regards, Zdenek Henek