Re: [Dev] String plus compiles to append
Yes, this has been the case for sometime where internally append is used.
Try the same with a loop.
On Tue, Dec 15, 2015 at 11:43 PM, Manuranga Perera wrote:
> I have compiled following class using javac 1.6.0_38
>
> class X{
> public String m(String a, String b, String c){
> return a + b + c;
> }
> }
>
>
> and decoupled using javap
>
>
> class X {
> X();
> Code:
>0: aload_0
>1: invokespecial #1 // Method
> java/lang/Object."":()V
>4: return
>
> public java.lang.String m(java.lang.String, java.lang.String,
> java.lang.String);
> Code:
>0: new #2 // class
> java/lang/StringBuilder
>3: dup
>4: invokespecial #3 // Method
> java/lang/StringBuilder."":()V
>7: aload_1
>8: invokevirtual #4 // Method
> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
> 11: aload_2
> 12: invokevirtual #4 // Method
> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
> 15: aload_3
> 16: invokevirtual #4 // Method
> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
> 19: invokevirtual #5 // Method
> java/lang/StringBuilder.toString:()Ljava/lang/String;
> 22: areturn
> }
>
> As you can see, there are three appends but only one StringBuilder
> objects. Therefor I purpose using plus instead of append in our code.
>
>
>
> --
> With regards,
> *Manu*ranga Perera.
>
> phone : 071 7 70 20 50
> mail : m...@wso2.com
>
--
*Afkham Azeez*
Director of Architecture; WSO2, Inc.; http://wso2.com
Member; Apache Software Foundation; http://www.apache.org/
*
*twitter: **http://twitter.com/afkham_azeez*
*linked-in: **http://lk.linkedin.com/in/afkhamazeez
*
*Lean . Enterprise . Middleware*
___
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Re: [Dev] String plus compiles to append
Hi All,
Please find comments inline.
Yes, this has been the case for sometime where internally append is used.
> Try the same with a loop.
+1 have tried this. Even though compiler is optimized to put StringBuilder
on multiple "+" concats not too *smart* to use the same StringBuilder
instance inside a loop.
Tried Test.java with a string concat inside a *loop*.
*Test.java*
class Test {
public static void main(String[] args) {
String content = "";
for (int i = 0; i < 10; i++) {
content = content + String.valueOf(i);
}
System.out.println(content);
}
}
*Constant pool:*
const #3 = class #24; // java/lang/StringBuilder
*Main Method:*
public static void main(java.lang.String[]);
Code:
0: ldc #2; //String
2: astore_1
3: iconst_0
4: istore_2
5: iload_2
6: bipush 10
8: if_icmpge 39
11: new #3; //class java/lang/StringBuilder <---*creating new String
builder each cycle*
14: dup
15: invokespecial #4; //Method java/lang/StringBuilder."":()V
18: aload_1
19: invokevirtual #5; //Method
java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
22: iload_2
23: invokestatic #6; //Method
java/lang/String.valueOf:(I)Ljava/lang/String;
26: invokevirtual #5; //Method
java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
29: invokevirtual #7; //Method
java/lang/StringBuilder.toString:()Ljava/lang/String;
32: astore_1
33: iinc 2, 1
36: goto 5 <--- *Jump for the loop*
39: getstatic #8; //Field java/lang/System.out:Ljava/io/PrintStream;
42: aload_1
43: invokevirtual #9; //Method
java/io/PrintStream.println:(Ljava/lang/String;)V
46: return
}
Thanks,
Rasika
On Wed, Dec 16, 2015 at 6:19 AM, Afkham Azeez wrote:
> Yes, this has been the case for sometime where internally append is used.
> Try the same with a loop.
>
> On Tue, Dec 15, 2015 at 11:43 PM, Manuranga Perera wrote:
>
>> I have compiled following class using javac 1.6.0_38
>>
>> class X{
>> public String m(String a, String b, String c){
>> return a + b + c;
>> }
>> }
>>
>>
>> and decoupled using javap
>>
>>
>> class X {
>> X();
>> Code:
>>0: aload_0
>>1: invokespecial #1 // Method
>> java/lang/Object."":()V
>>4: return
>>
>> public java.lang.String m(java.lang.String, java.lang.String,
>> java.lang.String);
>> Code:
>>0: new #2 // class
>> java/lang/StringBuilder
>>3: dup
>>4: invokespecial #3 // Method
>> java/lang/StringBuilder."":()V
>>7: aload_1
>>8: invokevirtual #4 // Method
>> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
>> 11: aload_2
>> 12: invokevirtual #4 // Method
>> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
>> 15: aload_3
>> 16: invokevirtual #4 // Method
>> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
>> 19: invokevirtual #5 // Method
>> java/lang/StringBuilder.toString:()Ljava/lang/String;
>> 22: areturn
>> }
>>
>> As you can see, there are three appends but only one StringBuilder
>> objects. Therefor I purpose using plus instead of append in our code.
>>
>>
>>
>> --
>> With regards,
>> *Manu*ranga Perera.
>>
>> phone : 071 7 70 20 50
>> mail : m...@wso2.com
>>
>
>
>
> --
> *Afkham Azeez*
> Director of Architecture; WSO2, Inc.; http://wso2.com
> Member; Apache Software Foundation; http://www.apache.org/
> *
> *twitter: **http://twitter.com/afkham_azeez*
>
> *linked-in: **http://lk.linkedin.com/in/afkhamazeez
> *
>
> *Lean . Enterprise . Middleware*
>
> ___
> Dev mailing list
> Dev@wso2.org
> http://wso2.org/cgi-bin/mailman/listinfo/dev
>
>
--
With Regards,
*Rasika Perera*
Software Engineer
M: +94 71 680 9060 E: rasi...@wso2.com
LinkedIn: http://lk.linkedin.com/in/rasika90
WSO2 Inc. www.wso2.com
lean.enterprise.middleware
___
Dev mailing list
Dev@wso2.org
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Re: [Dev] String plus compiles to append
My comment is about using plus out side of loops. Obviously we should use
StringBuilder when using loops. But we shouldn't uses it unnecessary
outside of loops since it affects readability.
On Thu, Dec 17, 2015 at 11:23 AM, Rasika Perera wrote:
> Hi All,
>
> Please find comments inline.
>
> Yes, this has been the case for sometime where internally append is used.
>> Try the same with a loop.
>
> +1 have tried this. Even though compiler is optimized to put StringBuilder
> on multiple "+" concats not too *smart* to use the same StringBuilder
> instance inside a loop.
>
> Tried Test.java with a string concat inside a *loop*.
>
> *Test.java*
> class Test {
> public static void main(String[] args) {
> String content = "";
> for (int i = 0; i < 10; i++) {
> content = content + String.valueOf(i);
> }
> System.out.println(content);
> }
> }
>
> *Constant pool:*
> const #3 = class #24; // java/lang/StringBuilder
>
> *Main Method:*
> public static void main(java.lang.String[]);
> Code:
>0: ldc #2; //String
>2: astore_1
>3: iconst_0
>4: istore_2
>5: iload_2
>6: bipush 10
>8: if_icmpge 39
>11: new #3; //class java/lang/StringBuilder <---*creating new
> String builder each cycle*
>14: dup
>15: invokespecial #4; //Method java/lang/StringBuilder."":()V
>18: aload_1
>19: invokevirtual #5; //Method
> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
>22: iload_2
>23: invokestatic #6; //Method
> java/lang/String.valueOf:(I)Ljava/lang/String;
>26: invokevirtual #5; //Method
> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
>29: invokevirtual #7; //Method
> java/lang/StringBuilder.toString:()Ljava/lang/String;
>32: astore_1
>33: iinc 2, 1
>36: goto 5 <--- *Jump for the loop*
>39: getstatic #8; //Field java/lang/System.out:Ljava/io/PrintStream;
>42: aload_1
>43: invokevirtual #9; //Method
> java/io/PrintStream.println:(Ljava/lang/String;)V
>46: return
> }
>
> Thanks,
> Rasika
>
> On Wed, Dec 16, 2015 at 6:19 AM, Afkham Azeez wrote:
>
>> Yes, this has been the case for sometime where internally append is used.
>> Try the same with a loop.
>>
>> On Tue, Dec 15, 2015 at 11:43 PM, Manuranga Perera wrote:
>>
>>> I have compiled following class using javac 1.6.0_38
>>>
>>> class X{
>>> public String m(String a, String b, String c){
>>> return a + b + c;
>>> }
>>> }
>>>
>>>
>>> and decoupled using javap
>>>
>>>
>>> class X {
>>> X();
>>> Code:
>>>0: aload_0
>>>1: invokespecial #1 // Method
>>> java/lang/Object."":()V
>>>4: return
>>>
>>> public java.lang.String m(java.lang.String, java.lang.String,
>>> java.lang.String);
>>> Code:
>>>0: new #2 // class
>>> java/lang/StringBuilder
>>>3: dup
>>>4: invokespecial #3 // Method
>>> java/lang/StringBuilder."":()V
>>>7: aload_1
>>>8: invokevirtual #4 // Method
>>> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
>>> 11: aload_2
>>> 12: invokevirtual #4 // Method
>>> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
>>> 15: aload_3
>>> 16: invokevirtual #4 // Method
>>> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
>>> 19: invokevirtual #5 // Method
>>> java/lang/StringBuilder.toString:()Ljava/lang/String;
>>> 22: areturn
>>> }
>>>
>>> As you can see, there are three appends but only one StringBuilder
>>> objects. Therefor I purpose using plus instead of append in our code.
>>>
>>>
>>>
>>> --
>>> With regards,
>>> *Manu*ranga Perera.
>>>
>>> phone : 071 7 70 20 50
>>> mail : m...@wso2.com
>>>
>>
>>
>>
>> --
>> *Afkham Azeez*
>> Director of Architecture; WSO2, Inc.; http://wso2.com
>> Member; Apache Software Foundation; http://www.apache.org/
>> *
>> *twitter: **http://twitter.com/afkham_azeez*
>>
>> *linked-in: **http://lk.linkedin.com/in/afkhamazeez
>> *
>>
>> *Lean . Enterprise . Middleware*
>>
>> ___
>> Dev mailing list
>> Dev@wso2.org
>> http://wso2.org/cgi-bin/mailman/listinfo/dev
>>
>>
>
>
> --
> With Regards,
>
> *Rasika Perera*
> Software Engineer
> M: +94 71 680 9060 E: rasi...@wso2.com
> LinkedIn: http://lk.linkedin.com/in/rasika90
>
> WSO2 Inc. www.wso2.com
> lean.enterprise.middleware
>
--
With regards,
*Manu*ranga Perera.
phone : 071 7 70 20 50
mail : m...@wso2.com
___
Dev mailing list
Dev@wso2.org
http://wso2.org/cgi-bin/mailman/listinfo/dev
Re: [Dev] String plus compiles to append
+1
On Thu, Dec 17, 2015 at 1:55 PM, Manuranga Perera wrote:
> My comment is about using plus out side of loops. Obviously we should use
> StringBuilder when using loops. But we shouldn't uses it unnecessary
> outside of loops since it affects readability.
>
> On Thu, Dec 17, 2015 at 11:23 AM, Rasika Perera wrote:
>
>> Hi All,
>>
>> Please find comments inline.
>>
>> Yes, this has been the case for sometime where internally append is used.
>>> Try the same with a loop.
>>
>> +1 have tried this. Even though compiler is optimized to put
>> StringBuilder on multiple "+" concats not too *smart* to use the same
>> StringBuilder instance inside a loop.
>>
>> Tried Test.java with a string concat inside a *loop*.
>>
>> *Test.java*
>> class Test {
>> public static void main(String[] args) {
>> String content = "";
>> for (int i = 0; i < 10; i++) {
>> content = content + String.valueOf(i);
>> }
>> System.out.println(content);
>> }
>> }
>>
>> *Constant pool:*
>> const #3 = class #24; // java/lang/StringBuilder
>>
>> *Main Method:*
>> public static void main(java.lang.String[]);
>> Code:
>>0: ldc #2; //String
>>2: astore_1
>>3: iconst_0
>>4: istore_2
>>5: iload_2
>>6: bipush 10
>>8: if_icmpge 39
>>11: new #3; //class java/lang/StringBuilder <---*creating new
>> String builder each cycle*
>>14: dup
>>15: invokespecial #4; //Method java/lang/StringBuilder."":()V
>>18: aload_1
>>19: invokevirtual #5; //Method
>> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
>>22: iload_2
>>23: invokestatic #6; //Method
>> java/lang/String.valueOf:(I)Ljava/lang/String;
>>26: invokevirtual #5; //Method
>> java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
>>29: invokevirtual #7; //Method
>> java/lang/StringBuilder.toString:()Ljava/lang/String;
>>32: astore_1
>>33: iinc 2, 1
>>36: goto 5 <--- *Jump for the loop*
>>39: getstatic #8; //Field java/lang/System.out:Ljava/io/PrintStream;
>>42: aload_1
>>43: invokevirtual #9; //Method
>> java/io/PrintStream.println:(Ljava/lang/String;)V
>>46: return
>> }
>>
>> Thanks,
>> Rasika
>>
>> On Wed, Dec 16, 2015 at 6:19 AM, Afkham Azeez wrote:
>>
>>> Yes, this has been the case for sometime where internally append is
>>> used. Try the same with a loop.
>>>
>>> On Tue, Dec 15, 2015 at 11:43 PM, Manuranga Perera
>>> wrote:
>>>
I have compiled following class using javac 1.6.0_38
class X{
public String m(String a, String b, String c){
return a + b + c;
}
}
and decoupled using javap
class X {
X();
Code:
0: aload_0
1: invokespecial #1 // Method
java/lang/Object."":()V
4: return
public java.lang.String m(java.lang.String, java.lang.String,
java.lang.String);
Code:
0: new #2 // class
java/lang/StringBuilder
3: dup
4: invokespecial #3 // Method
java/lang/StringBuilder."":()V
7: aload_1
8: invokevirtual #4 // Method
java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
11: aload_2
12: invokevirtual #4 // Method
java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
15: aload_3
16: invokevirtual #4 // Method
java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
19: invokevirtual #5 // Method
java/lang/StringBuilder.toString:()Ljava/lang/String;
22: areturn
}
As you can see, there are three appends but only one StringBuilder
objects. Therefor I purpose using plus instead of append in our code.
--
With regards,
*Manu*ranga Perera.
phone : 071 7 70 20 50
mail : m...@wso2.com
>>>
>>>
>>>
>>> --
>>> *Afkham Azeez*
>>> Director of Architecture; WSO2, Inc.; http://wso2.com
>>> Member; Apache Software Foundation; http://www.apache.org/
>>> *
>>> *twitter: **http://twitter.com/afkham_azeez*
>>>
>>> *linked-in: **http://lk.linkedin.com/in/afkhamazeez
>>> *
>>>
>>> *Lean . Enterprise . Middleware*
>>>
>>> ___
>>> Dev mailing list
>>> Dev@wso2.org
>>> http://wso2.org/cgi-bin/mailman/listinfo/dev
>>>
>>>
>>
>>
>> --
>> With Regards,
>>
>> *Rasika Perera*
>> Software Engineer
>> M: +94 71 680 9060 E: rasi...@wso2.com
>> LinkedIn: http://lk.linkedin.com/in/rasika90
>>
>> WSO2 Inc. www.wso2.com
>> lean.ent
