设置一些测试

.vscode/launch.json

@@ -0,0 +1,43 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+        "type": "java",
+        "name": "Adult",
+        "request": "launch",
+        "mainClass": "effectivejava.chapter2.item8.Adult",
+        "projectName": "effective-java-3e-source-code_616714c9"
+    },
+    {
+        "type": "java",
+        "name": "Run RomanNumerals with args",
+        "request": "launch",
+        "mainClass": "effectivejava.chapter2.item6.RomanNumerals",
+        "args": [
+            "5",
+            "1000"
+        ]
+    },
+    {
+        "type": "java",
+        "name": "Run Sum with args",
+        "request": "launch",
+        "mainClass": "effectivejava.chapter2.item6.Sum",
+        "args": [
+            "1"
+        ]
+    },
+    {
+        "type": "java",
+        "name": "Run Operation with args",
+        "request": "launch",
+        "mainClass": "effectivejava.chapter7.item42.Operation",
+        "args": [
+            "2",
+            "3"
+        ]
+    }
+]
+}
+
+

src/effectivejava/chapter2/item6/RomanNumerals.java

@@ -26,7 +26,7 @@ public static void main(String[] args) {
         for (int i = 0; i < numSets; i++) {
             long start = System.nanoTime();
             for (int j = 0; j < numReps; j++) {
-                b ^= isRomanNumeralSlow("MCMLXXVI");  // Change Slow to Fast to see performance difference
+                b ^= isRomanNumeralFast("MCMLXXVI");  // Change Slow to Fast to see performance difference
             }
             long end = System.nanoTime();
             System.out.println(((end - start) / (1_000. * numReps)) + " μs.");

src/effectivejava/chapter2/item6/Sum.java

@@ -5,7 +5,7 @@
 // Hideously slow program! Can you spot the object creation? (Page 24)
 public class Sum {
     private static long sum() {
-        Long sum = 0L;
+        long sum = 0L;
         for (long i = 0; i <= Integer.MAX_VALUE; i++)
             sum += i;
         return sum;