CODEWITHSUNDEEP
javaeclipseintellij-idealambda
Knarf
Knarf

Reputation: 2156

Lambda suggestions in Eclipse like IntelliJ does

When in IntelliJ you enter some code like this :

Runnable cronTask = new Runnable() {
   @Override
   public void run() {
      // do something
   }
};

IntelliJ will automatically suggest that this will be better when using a lambda expression. And you have the option to do an automatic conversion to

Runnable cronTask = () -> {
   // do something
};

Is something like this possible in Eclipse ? Maybe with some kind of plugin ? I want Eclipse to give me warnings of where a lambda expression might be a better solution. And if possible also suggest the correct fix.

Upvotes: 6

Views: 4039

Answers (2)

VonC
VonC

Reputation: 1324733

Once you have "Use lambda when possible", you can now (Eclipse 2020.03) clean them up

A new clean-up has been added that simplifies the lambda expression and the method reference syntax and is enabled only for Java 8 and higher.

The clean up:

  • removes parenthesis for a single untyped parameter,
  • return statement for a single expression and
  • brackets for a single statement.

It replaces a lambda expression by a creation or a method reference when possible.

To select the clean up, invoke Source > Clean Up..., use a custom profile, and on the Configure... dialog select Simplify lambda expression and method reference syntax on the Code Style tab.

For the given code:

Lambda before cleanup -- https://www.eclipse.org/eclipse/news/4.15/images/lambda-expression-enhancements-before.png

You get this after the clean up:

Lambda after cleanup -- https://www.eclipse.org/eclipse/news/4.15/images/lambda-expression-enhancements-after.png

And with Eclipse 4.29 (Q3 2023), you now have:

Lambda Cleanup Improvements

A number of improvements have been made to the Java cleanups concerning converting to use lambdas and simplifying existing lambdas.

First of all, the cleanup preference: Convert functional interface instances on the Java Features tab for Java 8 has added an additional checkbox: Simplify method reference syntax for lambda conversions. This checkbox is selected by default and instructs the cleanup to use method reference syntax where possible when converting from anonymous classes. If the checkbox is unselected, method reference syntax will not be used by default (sometimes required to avoid a runtime NullPointerException) but will only be used if the user has also selected the Simplify lambda expression and method reference syntax cleanup option found on the Code Style tab.
By default, the Quick fix to convert an anonymous class will also by default now use the method reference syntax where possible.

New Lambda Cleanup Preference -- https://eclipse.dev/eclipse/news/4.29/images/new-lambda-pref.png

The second improvement to the lambda cleanups and quick fix is that the code now recognizes use of instanceof can be replaced with a method reference to isInstance.

The following code:

Lambda Cleanup Example Before

with the lambda cleanup will by default change to:

Lambda Cleanup Example After

Upvotes: 1

Pyves
Pyves

Reputation: 6483

To the best of my knowledge, there is no way to make Eclipse show compiler warnings where lambda expressions are a better alternative. Nevertheless, there is a nice feature that takes care of the automatic conversion you requested.

Right-click on any project or Java file, and select Source -> Clean Up... In the window that appears, select Use custom profile, and click Configure... In the Code Style tab, enable Convert functional interface instances, and make sure Use lambda where possible is selected, as shown in the screenshot below:

Lambda conversion

Validate and run the clean up. This feature alongside the manual Quick assist suggested by Timothy Truckle in the comments will hopefully cover most of your needs.

Upvotes: 8

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