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IntelliJ IDEA 2017.3.7 (Ultimate Edition)
Build #IU-173.4710.11, built on April 4, 2019
Licensed to Rover12421/Rover12421
You have a perpetual fallback license for this version
Subscription is active until December 31, 2099
JRE: 1.8.0_152-release-1024-b18 amd64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Windows 7 6.1

A newly created maven project, created by clicking next, resulted in the following error when newKafkaProducer<>.

Diamond types are not supported at this language level

You can see that Diamond is a feature of JDK1.7, so 1.5 is definitely not supported.

Right click on the project and select Open Module Setting

Open the following pop-up window, the error is that the default Language level here is still 5.0