BAEL-4494 | .toArray(new MyClass[0]) or .toArray(new MyClass[myList.size()])? (#10903)

* BAEL-4220 | A Guide to IllegalAccessError and when it happens

* BAEL-4220 | A Guide to IllegalAccessError and when it happens | fix tests

* BAEL-4220 | A Guide to IllegalAccessError and when it happens | fix tests

* BAEL-4220 | A Guide to IllegalAccessError and when it happens | BDD test names

* BAEL-4494 | .toArray(new MyClass[0]) or .toArray(new MyClass[myList.size()])?

* BAEL-4494 | .toArray(new MyClass[0]) or .toArray(new MyClass[myList.size()])?

Co-authored-by: root <anmoldeep0123@gmail.com>

core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/toarraycomparison/ToArrayBenchmark.java

@@ -0,0 +1,72 @@
+package com.baeldung.collections.toarraycomparison;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.TreeSet;
+import java.util.concurrent.TimeUnit;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+
+@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Fork(value = 3, jvmArgsAppend = { "-XX:+UseParallelGC", "-Xms4g", "-Xmx4g" })
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@State(Scope.Benchmark)
+public class ToArrayBenchmark {
+
+    @Param({ "10", "10000", "10000000" })
+    private int size;
+
+    @Param({ "array-list", "tree-set" })
+    private String type;
+
+    private Collection<String> collection;
+
+    @Setup
+    public void setup() {
+        switch (type) {
+        case "array-list":
+            collection = new ArrayList<String>();
+            break;
+        case "tree-set":
+            collection = new TreeSet<String>();
+            break;
+        default:
+            throw new UnsupportedOperationException();
+        }
+        for (int i = 0; i < size; i++) {
+            collection.add(String.valueOf(i));
+        }
+    }
+
+    @Benchmark
+    public String[] zero_sized() {
+        return collection.toArray(new String[0]);
+    }
+
+    @Benchmark
+    public String[] pre_sized() {
+        return collection.toArray(new String[collection.size()]);
+    }
+
+
+    public static void main(String[] args) {
+        try {
+            org.openjdk.jmh.Main.main(args);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}