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Support Article

Load Balancer health check fails with exception after upgrade



Load Balancer health check fails with NullPointerException after upgrade to Pega 7.3.1.

Error Messages

[   WebContainer : 0] [  STANDARD] [                    ] [       Apex:01.24.01] (ngineinterface.service.HttpAPI) ERROR  java.lang.NullPointerException
    at java.util.regex.Matcher.getTextLength( ~[?:1.8.0]
    at java.util.regex.Matcher.reset( ~[?:1.8.0]
    at java.util.regex.Matcher.<init>( ~[?:1.8.0]
    at java.util.regex.Pattern.matcher( ~[?:1.8.0]
    at com.pega.pegarules.exec.internal.PRExecProviderImpl.createClientDevice( ~[prprivate.jar:?]
    at com.pega.pegarules.session.internal.engineinterface.service.HttpAPI.initializeLocaleAndUserAgents( ~[prprivate.jar:?]
    at com.pega.pegarules.session.internal.engineinterface.service.HttpAPI.setThreadData( ~[prprivate.jar:?]
    at com.pega.pegarules.session.external.engineinterface.service.EngineAPI.processRequestInner( ~[prenginext.jar:?]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0]
    at sun.reflect.NativeMethodAccessorImpl.invoke( ~[?:1.8.0]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke( ~[?:1.8.0]
    at java.lang.reflect.Method.invoke( ~[?:2.6 (10-13-2016)]

Steps to Reproduce

  1. Upgrade from PRPC 6.2 to Pega 7.3.1
  2. Configure a health check 'ping' that calls /prweb/PRServlet
  3. Run the flow

Root Cause

The health check 'ping' was configured to access /prweb/PRServlet and to check both HTTP 200 and HTTP 303 as successful responses. 

A call to /prweb/PRServlet with a HTTP 303 response by default has a location header that adds directs the browser to the URL containing the unauthenticated AccessGroup hash. 

The client had a new prconfig.xml file that configured Authentication/RedirectGuests = false. With this prconfig.xml setting after the server restart, the redirection to HTTP 303 did not occur. 


Perform the following local-change:

Use the below REST service for Load Balancer health checks:




Published August 19, 2019 - Updated October 8, 2020

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