Are records syntactic sugar for classes?

Question

I recently discovered Java records, and it was amazing to learn about their existence and purpose.

However, I began to wonder if they are essentially just classes behind the scenes.

Does this mean that during compilation, they get converted into an explicit class with final private fields, a public constructor, and the necessary getters?

Answer 1

Under the hood it will still create a class (that's derived from java.lang.Record).

You can try it out yourself:

// test.java
record Test(int foo, String bar) {}

When you compile this with javac test.java and disassemble it again with javap Test you'll get this code:

final class Test extends java.lang.Record {
  Test(int, java.lang.String);
  public final java.lang.String toString();
  public final int hashCode();
  public final boolean equals(java.lang.Object);
  public int foo();
  public java.lang.String bar();
}