u need import

import java.util.Arrays

before class

sorry. JavaScript.

We can't really help unless you specify the language.

I can not use Object.fromEntries.
「TypeError: Object.fromEntries is not a function」

what error mean 「Unhandled rejection TestError: Value is not what was expected」

the Lock must be able to store different keys; each key must be verifiably unique (a Number can easily be copied)

my solution is here.

function Lock() {
  this.key = null
  this.createKey = function(){
    this.key = Number(new Date())
    return this.key
  }
  this.check = function(key){
    return this.key === key
  }
   this.expire = function(key){
      this.key = null
  }
}

this code can passed test. but attempt is not. above error occur.
why? should I need..

Test Results:
Lock
.createKey()
should return an object
Completed in 2ms
.check()
Unspecified AssertionError
.expire()
other keys should fail check
Completed in 5ms