BAEL-2015 Memory leaks in Java (#5295)

* BAEL-2015_Memory_leaks_in_Java * Ignored tests * Update NonStaticFieldsDemo.java * Corrected class name * converted tabspaces to whitespaces
2018-10-01 07:29:53 +05:30
parent b4aa279eaa
commit 317ed150a1
19 changed files with 410 additions and 0 deletions
@@ -0,0 +1,9 @@
+package com.baeldung.memoryleaks.equalshashcode;
+
+public class Person {
+    public String name;
+     
+    public Person(String name) {
+        this.name = name;
+    }
+}
@@ -0,0 +1,25 @@
+package com.baeldung.memoryleaks.equalshashcode;
+
+public class PersonOptimized {
+    public String name;
+     
+    public PersonOptimized(String name) {
+        this.name = name;
+    }
+     
+    @Override
+    public boolean equals(Object o) {
+        if (o == this) return true;
+        if (!(o instanceof PersonOptimized)) {
+            return false;
+        }
+        PersonOptimized person = (PersonOptimized) o;
+        return person.name.equals(name);
+    }
+     
+    @Override
+    public int hashCode() {
+        int result = 17;
+        result = 31 * result + name.hashCode();
+        return result;
+    }}
@@ -0,0 +1,32 @@
+package com.baeldung.memoryleaks.finalize;
+
+import java.nio.charset.Charset;
+import java.util.Random;
+
+public class BulkyObject {
+    private String data[];
+    
+    public BulkyObject() {
+        data = new String[1000000];
+        
+        for(int i=0; i<1000000; i++) {
+            data[i] = getRandomString();
+        }
+    }
+    
+    private String getRandomString() {
+        byte[] array = new byte[1000];
+        new Random().nextBytes(array);
+        return new String(array, Charset.forName("UTF-8"));
+    }
+    
+    @Override
+    public void finalize() {
+        try {
+            Thread.sleep(100);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        System.out.println("Finalizer called");
+    }
+}
@@ -0,0 +1,22 @@
+package com.baeldung.memoryleaks.finalize;
+
+import java.nio.charset.Charset;
+import java.util.Random;
+
+public class BulkyObjectOptimized {
+    private String data[];
+    
+    public BulkyObjectOptimized() {
+        data = new String[1000000];
+        
+        for(int i=0; i<1000000; i++) {
+            data[i] = getRandomString();
+        }
+    }
+    
+    private String getRandomString() {
+        byte[] array = new byte[1000];
+        new Random().nextBytes(array);
+        return new String(array, Charset.forName("UTF-8"));
+    }
+}
@@ -0,0 +1,22 @@
+package com.baeldung.memoryleaks.innerclass;
+
+import java.nio.charset.Charset;
+import java.util.Random;
+
+public class BulkyObject {
+    private String data[];
+    
+    public BulkyObject() {
+        data = new String[1000000];
+        
+        for(int i=0; i<1000000; i++) {
+            data[i] = getRandomString();
+        }
+    }
+    
+    private String getRandomString() {
+        byte[] array = new byte[1000];
+        new Random().nextBytes(array);
+        return new String(array, Charset.forName("UTF-8"));
+    }
+}
@@ -0,0 +1,17 @@
+package com.baeldung.memoryleaks.innerclass;
+
+public class InnerClassDriver {
+    public static InnerClassWrapper.SimpleInnerClass getSimpleInnerClassObj() {
+        return new InnerClassWrapper().new SimpleInnerClass();
+    }
+    
+    public static void main2(String[] args) {
+        InnerClassWrapper.SimpleInnerClass simpleInnerClassObj = getSimpleInnerClassObj();
+        System.out.println("Debug point");
+    }
+    
+    public static void main(String[] args) {
+        StaticNestedClassWrapper.StaticNestedClass simpleInnerClassObj = new StaticNestedClassWrapper.StaticNestedClass();
+        System.out.println("Debug point");
+    }
+}
@@ -0,0 +1,10 @@
+package com.baeldung.memoryleaks.innerclass;
+
+
+public class InnerClassWrapper {
+    private BulkyObject bulkyObject = new BulkyObject();
+    
+    public class SimpleInnerClass {
+        
+    }
+}
@@ -0,0 +1,10 @@
+package com.baeldung.memoryleaks.innerclass;
+
+
+public class StaticNestedClassWrapper {
+    private BulkyObject bulkyObject = new BulkyObject();
+    
+    public static class StaticNestedClass {
+        
+    }
+}
@@ -0,0 +1,17 @@
+package com.baeldung.memoryleaks.internedstrings;
+
+public class InternedString {
+    private static final String FILEPATH = "C:\\bigstring.txt";
+    
+    public void readString() {
+        String s1 = ReadStringFromFileUtil.read(FILEPATH).intern();
+        String s2 = ReadStringFromFileUtil.read(FILEPATH).intern();
+
+        if (s1 == s2) {
+            System.out.println("Both the strings objects are same");
+        }
+        else {
+            System.out.println("Both the strings objects are different");
+        }
+    }
+}
@@ -0,0 +1,34 @@
+package com.baeldung.memoryleaks.internedstrings;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+public class ReadStringFromFileUtil {
+
+    public static String read(String fileName) {
+        BufferedReader br = null;
+        try {
+            br = new BufferedReader(new FileReader(fileName));
+            StringBuilder sb = new StringBuilder();
+            String line = br.readLine();
+
+            while (line != null) {
+                sb.append(line);
+                sb.append("\n");
+                line = br.readLine();
+            }
+            return sb.toString();
+        } catch (IOException e) {
+            e.printStackTrace();
+        } finally {
+            try {
+                br.close();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+        return null;
+    }
+
+}
@@ -0,0 +1,17 @@
+package com.baeldung.memoryleaks.internedstrings;
+
+public class StringObject {
+    private static final String FILEPATH = "C:\\bigstring.txt";
+    
+    public void readString() {
+        String s1 = ReadStringFromFileUtil.read(FILEPATH);
+        String s2 = ReadStringFromFileUtil.read(FILEPATH);
+
+        if (s1 == s2) {
+            System.out.println("Both the strings objects are same");
+        }
+        else {
+            System.out.println("Both the strings objects are different");
+        }
+    }
+}
@@ -0,0 +1,21 @@
+package com.baeldung.memoryleaks.staticfields;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class NonStaticFieldsDemo {
+    public List<Double> list = new ArrayList<>();
+ 
+    public void populateList() {
+        for (int i = 0; i < 10000000; i++) {
+            list.add(Math.random());
+        }
+        System.out.println("Debug Point 2");
+    }
+ 
+    public static void main(String[] args) {
+        System.out.println("Debug Point 1");
+        new NonStaticFieldsDemo().populateList();
+        System.out.println("Debug Point 3");
+    }
+}
@@ -0,0 +1,21 @@
+package com.baeldung.memoryleaks.staticfields;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class StaticFieldsDemo {
+    public static List<Double> list = new ArrayList<>();
+ 
+    public void populateList() {
+        for (int i = 0; i < 10000000; i++) {
+            list.add(Math.random());
+        }
+        System.out.println("Debug Point 2");
+    }
+ 
+    public static void main(String[] args) {
+        System.out.println("Debug Point 1");
+        new StaticFieldsDemo().populateList();
+        System.out.println("Debug Point 3");
+    }
+}