What is the Java equivalent for LINQ? [closed]

Answer 1

JaQu is the LINQ equivalent for Java. Although it was developed for the H2 database, it should work for any database since it uses JDBC.

Answer 2

There's a very good library that you can use for this.

Located here: https://github.com/nicholas22/jpropel-light

Lambdas won't be available until Java 8 though, so using it is a bit different and doesn't feel as natural.

Answer 3

you can try this library: https://code.google.com/p/qood/

Here are some reasons to use it:

1. lightweight: only 9 public interface/class to learn.
2. query like SQL: support group-by, order-by, left join, formula,...etc.
3. for big data: use File(QFS) instead of Heap Memory.
4. try to solve Object-relational impedance mismatch.

Answer 4

See SBQL4J. It's type-safe strong query language integrated with Java. Allows to write complicated and multiply nested queries. There is a lot of operators, Java methods can be invoked inside queries so as constructors. Queries are translated to pure Java code (there is no reflection at runtime) so execution is very fast.

EDIT: Well, so far SBQL4J it's the ONLY extension to Java language which gives query capabilities similar to LINQ. There are some interesting project like Quaere and JaQue but they are only API's, not syntax / semantics extension with strong type safety in compile time.

Answer 5

Lambdas are now available within Java 8 in the form of JSR-335 - Lambda Expressions for the JavaTM Programming Language

UPDATE: JDK8 has now been released which contains project lambda. It's worth grabbing a copy of Java 8 in Action currently still MEAP.

Have a read of Brian Goetz articles relating to lambdas for a decent understanding of how lambdas are implemented within JDK8 while also gaining an understanding of streams, internal iteration, short-circuiting and constructor references.. Also check out the JSR's above to get further examples.

I've written a blog on some of the advantages of using lambdas in JDK8 called The Power of the Arrow, also NetBeans 8 has great support for converting constructs to JDK8 which I've also blogged about Migrating to JDK 8 with NetBeans.

Answer 6

As on 2014, I can finally say that LINQ is finally there in java 8.So no need to find an alternative of LINQ anymore.