[JAVA] I was addicted to the NoSuchMethodError in Cloud Endpoints

Overview

When creating Rest API using Cloud Endpoints in GAE / Java environment I was proceeding with the implementation by looking at Google Official Tutorial. At one point, I got a NoSuchMethodError and it stopped working properly.

com.google.apphosting.runtime.jetty9.JettyLogger warn: Error for /_ah/api/echo/v1/echo (JettyLogger.java:29)
java.lang.NoSuchMethodError: com.fasterxml.jackson.databind.ObjectReader.forType(Ljava/lang/Class;)Lcom/fasterxml/jackson/databind/ObjectReader;
	at com.google.api.server.spi.request.ServletRequestParamReader.deserializeParams(ServletRequestParamReader.java:177)
	at com.google.api.server.spi.request.RestServletRequestParamReader.read(RestServletRequestParamReader.java:135)
	at com.google.api.server.spi.SystemService.invokeServiceMethod(SystemService.java:349)
	at com.google.api.server.spi.handlers.EndpointsMethodHandler$RestHandler.handle(EndpointsMethodHandler.java:119)
	at com.google.api.server.spi.handlers.EndpointsMethodHandler$RestHandler.handle(EndpointsMethodHandler.java:102)
	at com.google.api.server.spi.dispatcher.PathDispatcher.dispatch(PathDispatcher.java:50)
	at com.google.api.server.spi.EndpointsServlet.service(EndpointsServlet.java:72)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:848)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1772)
	at com.google.api.control.ControlFilter.doFilter(ControlFilter.java:331)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1759)
	at com.google.api.control.ConfigFilter.doFilter(ConfigFilter.java:125)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1759)
	at com.google.apphosting.utils.servlet.JdbcMySqlConnectionCleanupFilter.doFilter(JdbcMySqlConnectionCleanupFilter.java:60)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1759)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:582)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:226)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
	at com.google.apphosting.runtime.jetty9.ParseBlobUploadHandler.handle(ParseBlobUploadHandler.java:120)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1182)
	at com.google.apphosting.runtime.jetty9.AppEngineWebAppContext.doHandle(AppEngineWebAppContext.java:171)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:512)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1112)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at com.google.apphosting.runtime.jetty9.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:297)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
	at org.eclipse.jetty.server.Server.handle(Server.java:539)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:333)
	at com.google.apphosting.runtime.jetty9.RpcConnection.handle(RpcConnection.java:202)
	at com.google.apphosting.runtime.jetty9.RpcConnector.serviceRequest(RpcConnector.java:81)
	at com.google.apphosting.runtime.jetty9.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:123)
	at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.dispatchServletRequest(JavaRuntime.java:692)
	at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.dispatchRequest(JavaRuntime.java:654)
	at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:624)
	at com.google.apphosting.runtime.JavaRuntime$NullSandboxRequestRunnable.run(JavaRuntime.java:818)
	at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:274)
	at java.lang.Thread.run(Thread.java:745)

How to improve

Here's how to improve it in my environment.

The problem was that there were multiple jar files in the library called jackson-core, causing inconsistencies. At the same time as CloudEndpoints, Jacson core was described in the pom.xml file to create a dependency, which seems to have caused an inconsistency.

I removed the jackson-core related library that I added independently because I wanted to use ObjectMapper, and tried deploying it again. It was confirmed that the processing was performed correctly.

Reference material

https://groups.google.com/forum/#!topic/google-cloud-endpoints/Rf7f9GreGGs