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Android Kotlin for Java Developers Is This Thing On? It's Alive!

The GameTest is taking forever and then going into OutOfMemory error. I'm not sure what is it that I'm doing wrong.

The GameTest is taking forever and then going into OutOfMemory error. I'm not sure what is it that I'm doing wrong. May be the 10000 iterations is a lot.

The whole error looks like this. java.lang.OutOfMemoryError: Java heap space

at java.util.Arrays.copyOf(Arrays.java:3181)
at java.util.ArrayList.grow(ArrayList.java:261)
at java.util.ArrayList.ensureExplicitCapacity(ArrayList.java:235)
at java.util.ArrayList.ensureCapacityInternal(ArrayList.java:227)
at java.util.ArrayList.addAll(ArrayList.java:579)
at TableauPile.addCards(TableauPile.kt:14)
at GameModel.playCard(GameModel.kt:84)
at GameModel.playCards(GameModel.kt:66)
at GameModel.onTableauTap(GameModel.kt:58)
at GamePresenter.onTableauTap(GamePresenter.kt:28)
at GameTest.kingInFirstFoundationPile(GameTest.kt:21)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)

And the Game looks exactly the same as taught in the videos. The GameTest class looks like this.

class GameTest {
    fun kingInFirstFoundationPile() {
        // arrange
        var numGames = 0
        val maxGames = 10000

        // act
        for (i in 1..maxGames) {
            for (j in 1..100) {
                GameModel.tableauPiles.forEachIndexed { index, tableauPile ->
                    GamePresenter.onTableauTap(index, tableauPile.cards.lastIndex)
            if (GameModel.foundationPiles[0].cards.size == 13) {

        // assert
        println("# Games: $numGames")
        assert(numGames < maxGames)
Ben Deitch
Ben Deitch
Treehouse Teacher

Hmm. What happens if you change maxGames to something like 1000? Also, if you upload your project to GitHub I can run it and see if I get the same issue.

Ok. Put it on the Github. Check this link out.


1 Answer

Ben Deitch
Ben Deitch
Treehouse Teacher

Found it!

On lines 14 and 18 of TableauPile.kt you've got:


and it needs to be:


Hope that helps!