Extracting a method does not detect other similar code fragments and replace them with invocation to new method.  Extracting a method should have an effect as shown below.  But currently it replaces only at the location from which the refactoring was initiated.

Before Refactoring:

public class Sample { 
    public void method1(String str) { 
        String newStr = str + "_abc"; 
        // Do something on newStr. 
    } 
    public void method2(String anotherStr) { 
        String anotherNewStr = anotherStr + "_abc"; 
        // Do something else on anotherNewStr. 
    } 
}

After Refactoring: 

public class Sample { 
    public void method1(String str) { 
        String newStr = addSuffix(str); 
        // Do something on newStr. 
    } 

    public void method2(String anotherStr) { 
        String anotherNewStr = addSuffix(anotherStr); 
        // Do something else on anotherNewStr. 
    } 

    private String addSuffix(String anotherStr) { 
        return anotherStr + "_abc"; 
    } 
}