问题:

I am using NetBeans 8. When my code contains a Lambda expression and I try to compile, I get the following error message:

lambda expression not expected here

lambda expressions are not supported in -source 1.5
  (use -source 8 or higher to enable lambda expressions)
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(Alt-Enter shows hints)

回答1:

Change compiler version of your source code into your project properties to jdk 8 and firstly check whether you have installed one.

回答2:

Please click right from you project -> Properties -> Choose Sources -> (you will see Source/Binary Format) change it to 1.8 -> Click OK.

Or you can see in this link http://tinadev.blogspot.com/2015/08/lambda-expression-not-expected-here.html

Thanks

回答3:

In the project properties dialog, select Sources in the left panel and then on the bottom right look for "Source/Binary Format" Change that to JDK 8.

回答4:

Download JDK 1.8 to resolve this issue. change the JAVA_HOME environment variables path to jdk_1.8. Right Click on the project folder which has the above mentioned compilation error and select properties. In Sources tab change the source/binary format to JDK 8. In libraries change Java Platform to JDK 1.8.