delete extra comments and variable assignments, use guava precondition for check

spring-core/pom.xml

@@ -50,6 +50,11 @@
             <version>4.12</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>20.0</version>
+        </dependency>
     </dependencies>
 
     <build>

spring-core/src/main/java/com/baeldung/factorybean/InitializationToolFactory.java

@@ -1,22 +1,21 @@
 package com.baeldung.factorybean;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.InitializingBean;
+import org.springframework.util.StringUtils;
 
 public class InitializationToolFactory implements FactoryBean<Tool>, InitializingBean {
-    private int factoryId;// standard setters and getters
+    private int factoryId;
-    private int toolId;// standard setters and getters
+    private int toolId;
-    private String toolName;// standard setters and getters
+    private String toolName;
-    private double toolPrice;// standard setters and getters
+    private double toolPrice;
 
     @Override
     public void afterPropertiesSet() throws Exception {
-        if (toolName == null || toolName.equals("")) {
+        checkArgument(!StringUtils.isEmpty(toolName), "tool name cannot be empty");
-            throw new IllegalArgumentException("tool name cannot be empty");
+        checkArgument(toolPrice >= 0, "tool price should not be less than 0");
-        }
-        if (toolPrice < 0) {
-            throw new IllegalArgumentException("tool price should not be less than 0");
-        }
     }
 
     @Override

spring-core/src/main/java/com/baeldung/factorybean/NonSingleToolFactory.java

@@ -3,10 +3,10 @@ package com.baeldung.factorybean;
 import org.springframework.beans.factory.config.AbstractFactoryBean;
 
 public class NonSingleToolFactory extends AbstractFactoryBean<Tool> {
-    private int factoryId;// standard setters and getters
+    private int factoryId;
-    private int toolId;// standard setters and getters
+    private int toolId;
-    private String toolName;// standard setters and getters
+    private String toolName;
-    private double toolPrice;// standard setters and getters
+    private double toolPrice;
 
     public NonSingleToolFactory() {
         setSingleton(false);

spring-core/src/main/java/com/baeldung/factorybean/PostConstructToolFactory.java

@@ -1,14 +1,17 @@
 package com.baeldung.factorybean;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import javax.annotation.PostConstruct;
 
 import org.springframework.beans.factory.FactoryBean;
+import org.springframework.util.StringUtils;
 
 public class PostConstructToolFactory implements FactoryBean<Tool> {
-    private int factoryId;// standard setters and getters
+    private int factoryId;
-    private int toolId;// standard setters and getters
+    private int toolId;
-    private String toolName;// standard setters and getters
+    private String toolName;
-    private double toolPrice;// standard setters and getters
+    private double toolPrice;
 
     @Override
     public Tool getObject() throws Exception {
@@ -27,12 +30,8 @@ public class PostConstructToolFactory implements FactoryBean<Tool> {
 
     @PostConstruct
     public void checkParams() {
-        if (toolName == null || toolName.equals("")) {
+        checkArgument(!StringUtils.isEmpty(toolName), "tool name cannot be empty");
-            throw new IllegalArgumentException("tool name cannot be empty");
+        checkArgument(toolPrice >= 0, "tool price should not be less than 0");
-        }
-        if (toolPrice < 0) {
-            throw new IllegalArgumentException("tool price should not be less than 0");
-        }
     }
 
     public int getFactoryId() {

spring-core/src/main/java/com/baeldung/factorybean/SingleToolFactory.java

@@ -4,10 +4,10 @@ import org.springframework.beans.factory.config.AbstractFactoryBean;
 
 //no need to set singleton property because default value is true
 public class SingleToolFactory extends AbstractFactoryBean<Tool> {
-    private int factoryId;// standard setters and getters
+    private int factoryId;
-    private int toolId;// standard setters and getters
+    private int toolId;
-    private String toolName;// standard setters and getters
+    private String toolName;
-    private double toolPrice;// standard setters and getters
+    private double toolPrice;
 
     @Override
     public Class<?> getObjectType() {

spring-core/src/main/java/com/baeldung/factorybean/Tool.java

@@ -1,9 +1,9 @@
 package com.baeldung.factorybean;
 
 public class Tool {
-    private int id;// standard setters and getters
+    private int id;
-    private String name;// standard setters and getters
+    private String name;
-    private double price;// standard setters and getters
+    private double price;
 
     public Tool() {
     }

spring-core/src/main/java/com/baeldung/factorybean/ToolFactory.java

@@ -3,10 +3,10 @@ package com.baeldung.factorybean;
 import org.springframework.beans.factory.FactoryBean;
 
 public class ToolFactory implements FactoryBean<Tool> {
-    private int factoryId;// standard setters and getters
+    private int factoryId;
-    private int toolId;// standard setters and getters
+    private int toolId;
-    private String toolName;// standard setters and getters
+    private String toolName;
-    private double toolPrice;// standard setters and getters
+    private double toolPrice;
 
     @Override
     public Tool getObject() throws Exception {

spring-core/src/main/java/com/baeldung/factorybean/Worker.java

@@ -1,8 +1,8 @@
 package com.baeldung.factorybean;
 
 public class Worker {
-    private String number;// standard setters and getters
+    private String number;
-    private Tool tool;// standard setters and getters
+    private Tool tool;
 
     public Worker() {
     }

spring-core/src/main/resources/factorybean-abstract-spring-ctx.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<beans xmlns="http://www.springframework.org/schema/beans"
+<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns="http://www.springframework.org/schema/beans"
        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
 
     <bean id="singleTool" class="com.baeldung.factorybean.SingleToolFactory">

spring-core/src/main/resources/factorybean-init-spring-ctx.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<beans xmlns="http://www.springframework.org/schema/beans"
+<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns="http://www.springframework.org/schema/beans"
        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
 
     <bean id="initializationTool" class="com.baeldung.factorybean.InitializationToolFactory">

spring-core/src/main/resources/factorybean-postconstruct-spring-ctx.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<beans xmlns="http://www.springframework.org/schema/beans"
+<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:context="http://www.springframework.org/schema/context"
+       xmlns="http://www.springframework.org/schema/beans"
        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
 
     <context:annotation-config/>

spring-core/src/main/resources/factorybean-spring-ctx.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<beans xmlns="http://www.springframework.org/schema/beans"
+<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns="http://www.springframework.org/schema/beans"
        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
 
     <bean id="tool" class="com.baeldung.factorybean.ToolFactory">

spring-core/src/test/java/com/baeldung/factorybean/FactoryBeanInitializeTest.java

@@ -1,17 +1,16 @@
 package com.baeldung.factorybean;
 
 import org.junit.Test;
-import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
 
 public class FactoryBeanInitializeTest {
     @Test(expected = Exception.class)
     public void testInitializationToolFactory() {
-        ApplicationContext context = new ClassPathXmlApplicationContext("classpath:factorybean-init-spring-ctx.xml");
+        new ClassPathXmlApplicationContext("classpath:factorybean-init-spring-ctx.xml");
     }
 
     @Test(expected = Exception.class)
     public void testPostConstructToolFactory() {
-        ApplicationContext context = new ClassPathXmlApplicationContext("classpath:factorybean-postconstruct-spring-ctx.xml");
+        new ClassPathXmlApplicationContext("classpath:factorybean-postconstruct-spring-ctx.xml");
     }
 }