# Payara, "java.lang.NoSuchMethodError: com.google.common.collect..."  Problem and Solution

Payara Server loads own libraries / jars like e.g. Google's Guava first.
In case your application uses a recent feature (e.g. a method) in a newer version of such a library, 
you will get an exception like: 

Caused by: java.lang.NoSuchMethodError: com.google.common.collect.Sets$SetView.iterator()Lcom/google/common/collect/UnmodifiableIterator;


Turning off the class loader delegation solves the problem:



<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE payara-web-app PUBLIC "-//Payara.fish//DTD Payara Server 4 Servlet 3.0//EN" "https://docs.payara.fish/schemas/payara-web-app_4.dtd">
    <payara-web-app error-url="">
    <class-loader delegate="false"/>
</payara-web-app>



However, a code refactoring and the removal of the dependency from the pom.xml and using Java 8+ / Java EE features only will make your WARs thinner
and docker deployments faster:






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