It seems that the underlying maven library code would need to explicitly set up proper executable location.   

org.onap.policy.brms.api.BrmsPush.buildAndGenerateJarFile(BrmsPush.java:822)

org.apache.maven.shared.invoker.CommandLineConfigurationException: Maven executable not found at: /usr/share/maven/bin/mvn

in $POLICY_LOGS/policy-api/error.log

2019-03-25T14:22:54.248+00:00||WebSocketConnectReadThread-31|||||ERROR|POLICY-519E||POLICY-519E ERROR: PE500 - Process Flow Issue: Maven Invocation issue for policy-amsterdam-rulesError configuring command-line. Reason: Maven executable not found at: /usr/share/maven/bin/mvn:org.apache.maven.shared.invoker.MavenInvocationException: Error configuring command-line. Reason: Maven executable not found at: /usr/share/maven/bin/mvn - at org.apache.maven.shared.invoker.DefaultInvoker.execute(DefaultInvoker.java:104) - at org.onap.policy.brms.api.BrmsPush.buildAndGenerateJarFile(BrmsPush.java:822) - at org.onap.policy.brms.api.BrmsPush.pushRules(BrmsPush.java:786) - at org.onap.policy.brms.api.BrmsHandler.runOnNotification(BrmsHandler.java:146) - at org.onap.policy.brms.api.BrmsHandler.notificationReceived(BrmsHandler.java:75) - at org.onap.policy.std.AutoClientEnd.callHandler(AutoClientEnd.java:235) - at org.onap.policy.std.AutoClientEnd.onMessage(AutoClientEnd.java:70) - at org.java_websocket.client.WebSocketClient.onWebsocketMessage(WebSocketClient.java:462) - at org.java_websocket.drafts.Draft_6455.processFrame(Draft_6455.java:696) - at org.java_websocket.WebSocketImpl.decodeFrames(WebSocketImpl.java:367) - at org.java_websocket.WebSocketImpl.decode(WebSocketImpl.java:212) - at org.java_websocket.client.WebSocketClient.run(WebSocketClient.java:389) - at java.lang.Thread.run(Thread.java:748) - Caused by: org.apache.maven.shared.invoker.CommandLineConfigurationException: Maven executable not found at: /usr/share/maven/bin/mvn - at org.apache.maven.shared.invoker.MavenCommandLineBuilder.findMavenExecutable(MavenCommandLineBuilder.java:600) - at org.apache.maven.shared.invoker.MavenCommandLineBuilder.build(MavenCommandLineBuilder.java:71) - at org.apache.maven.shared.invoker.DefaultInvoker.execute(DefaultInvoker.java:100) - ... 12 more - 2019-03-25T14:22:54.248+00:00||WebSocketConnectReadThread-31|||||ERROR|POLICY-519E||POLICY-519E ERROR: PE500 - Process Flow Issue: Maven Invocation issue for policy-amsterdam-rulesError configuring command-line. Reason: Maven executable not found at: /usr/share/maven/bin/mvn:org.apache.maven.shared.invoker.MavenInvocationException: Error configuring command-line. Reason: Maven executable not found at: /usr/share/maven/bin/mvn - at org.apache.maven.shared.invoker.DefaultInvoker.execute(DefaultInvoker.java:104) - at org.onap.policy.brms.api.BrmsPush.buildAndGenerateJarFile(BrmsPush.java:822) - at org.onap.policy.brms.api.BrmsPush.pushRules(BrmsPush.java:786) - at org.onap.policy.brms.api.BrmsHandler.runOnNotification(BrmsHandler.java:146) - at org.onap.policy.brms.api.BrmsHandler.notificationReceived(BrmsHandler.java:75) - at org.onap.policy.std.AutoClientEnd.callHandler(AutoClientEnd.java:235) - at org.onap.policy.std.AutoClientEnd.onMessage(AutoClientEnd.java:70) - at org.java_websocket.client.WebSocketClient.onWebsocketMessage(WebSocketClient.java:462) - at org.java_websocket.drafts.Draft_6455.processFrame(Draft_6455.java:696) - at org.java_websocket.WebSocketImpl.decodeFrames(WebSocketImpl.java:367) - at org.java_websocket.WebSocketImpl.decode(WebSocketImpl.java:212) - at org.java_websocket.client.WebSocketClient.run(WebSocketClient.java:389) - at java.lang.Thread.run(Thread.java:748) - Caused by: org.apache.maven.shared.invoker.CommandLineConfigurationException: Maven executable not found at: /usr/share/maven/bin/mvn - at org.apache.maven.shared.invoker.MavenCommandLineBuilder.findMavenExecutable(MavenCommandLineBuilder.java:600) - at org.apache.maven.shared.invoker.MavenCommandLineBuilder.build(MavenCommandLineBuilder.java:71) - at org.apache.maven.shared.invoker.DefaultInvoker.execute(DefaultInvoker.java:100) - ... 12 more - 

[/opt/app/policy/servers/brmsgw] which mvn
/usr/bin/mvn