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Support Article

htmltopdf is failing - NoClassDefFoundError PD4ML



On certain nodes, activity htmltopdf fails occassionally with NoClassDefFoundError.

Error Messages

java.lang.NoClassDefFoundError: org/zefer/pd4ml/PD4ML
at com.pega.pegarules.integration.engine.internal.util.PDFUtilsImpl.generatePDF(
at com.pega.pegarules.integration.engine.internal.util.PDFUtilsImpl.generatePDF(
at com.pegarules.generated.activity.ra_action_htmltopdf_792606314b43fb77dd0c23e4d76f4526.step3_circum0(
at com.pegarules.generated.activity.ra_action_htmltopdf_792606314b43fb77dd0c23e4d76f4526.perform(
at com.pega.pegarules.session.internal.mgmt.Executable.doActivity(
at com.pegarules.generated.activity.ra_action_sendinquirytopdf_c36e70bc0ce219331f3967adbdf00c01.step16_circum0(
at com.pegarules.generated.activity.ra_action_
at com.pega.pegarules.session.internal.mgmt.Executable.doActivity(

Steps to Reproduce

Run a flow that includes 'htmltopdf' on one of the affected nodes

Root Cause

This is a flaw in PRPC classloader and the root cause is unknown at this point.


There are two ways to temporarily resolve this issue.
Please contact Pegasystems GCS to troubleshoot the issue further in order to find a permanent solution.
1. Restart the JVM. This should reset the classloader and the issue may go away.
2. Go to SMA application> Advanced> Classloader Management and
select htmltopdf and/or your custom activity (sendinquirytopdf in this case) Class and 'Remove from Cache'. This should force classloader to reload the class again from the database when referenced in the flow.

Published February 15, 2016 - Updated October 8, 2020

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