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Using only 1 System.out.print() instead of 3. More details below [duplicate]

I am trying to concatenate strings in Java. Why isn't this working?
public class StackOverflowTest {
public static void main(String args[]) {
int theNumber = 42;
System.out.println("Your number is " . theNumber . "!");
}
}

You can concatenate Strings using the + operator:
System.out.println("Your number is " + theNumber + "!");
theNumber is implicitly converted to the String "42".

The concatenation operator in java is +, not .
Read this (including all subsections) before you start. Try to stop thinking the php way ;)
To broaden your view on using strings in Java - the + operator for strings is actually transformed (by the compiler) into something similar to:
new StringBuilder().append("firstString").append("secondString").toString()

There are two basic answers to this question:
[simple] Use the + operator (string concatenation). "your number is" + theNumber + "!" (as noted elsewhere)
[less simple]: Use StringBuilder (or StringBuffer).
StringBuilder value;
value.append("your number is");
value.append(theNumber);
value.append("!");
value.toString();
I recommend against stacking operations like this:
new StringBuilder().append("I").append("like to write").append("confusing code");
Edit: starting in java 5 the string concatenation operator is translated into StringBuilder calls by the compiler. Because of this, both methods above are equal.
Note: Spaceisavaluablecommodity,asthissentancedemonstrates.
Caveat: Example 1 below generates multiple StringBuilder instances and is less efficient than example 2 below
Example 1
String Blam = one + two;
Blam += three + four;
Blam += five + six;
Example 2
String Blam = one + two + three + four + five + six;

Out of the box you have 3 ways to inject the value of a variable into a String as you try to achieve:
1. The simplest way
You can simply use the operator + between a String and any object or primitive type, it will automatically concatenate the String and
In case of an object, the value of String.valueOf(obj) corresponding to the String "null" if obj is null otherwise the value of obj.toString().
In case of a primitive type, the equivalent of String.valueOf(<primitive-type>).
Example with a non null object:
Integer theNumber = 42;
System.out.println("Your number is " + theNumber + "!");
Output:
Your number is 42!
Example with a null object:
Integer theNumber = null;
System.out.println("Your number is " + theNumber + "!");
Output:
Your number is null!
Example with a primitive type:
int theNumber = 42;
System.out.println("Your number is " + theNumber + "!");
Output:
Your number is 42!
2. The explicit way and potentially the most efficient one
You can use StringBuilder (or StringBuffer the thread-safe outdated counterpart) to build your String using the append methods.
Example:
int theNumber = 42;
StringBuilder buffer = new StringBuilder()
.append("Your number is ").append(theNumber).append('!');
System.out.println(buffer.toString()); // or simply System.out.println(buffer)
Output:
Your number is 42!
Behind the scene, this is actually how recent java compilers convert all the String concatenations done with the operator +, the only difference with the previous way is that you have the full control.
Indeed, the compilers will use the default constructor so the default capacity (16) as they have no idea what would be the final length of the String to build, which means that if the final length is greater than 16, the capacity will be necessarily extended which has price in term of performances.
So if you know in advance that the size of your final String will be greater than 16, it will be much more efficient to use this approach to provide a better initial capacity. For instance, in our example we create a String whose length is greater than 16, so for better performances it should be rewritten as next:
Example optimized :
int theNumber = 42;
StringBuilder buffer = new StringBuilder(18)
.append("Your number is ").append(theNumber).append('!');
System.out.println(buffer)
Output:
Your number is 42!
3. The most readable way
You can use the methods String.format(locale, format, args) or String.format(format, args) that both rely on a Formatter to build your String. This allows you to specify the format of your final String by using place holders that will be replaced by the value of the arguments.
Example:
int theNumber = 42;
System.out.println(String.format("Your number is %d!", theNumber));
// Or if we need to print only we can use printf
System.out.printf("Your number is still %d with printf!%n", theNumber);
Output:
Your number is 42!
Your number is still 42 with printf!
The most interesting aspect with this approach is the fact that we have a clear idea of what will be the final String because it is much more easy to read so it is much more easy to maintain.

The java 8 way:
StringJoiner sj1 = new StringJoiner(", ");
String joined = sj1.add("one").add("two").toString();
// one, two
System.out.println(joined);
StringJoiner sj2 = new StringJoiner(", ","{", "}");
String joined2 = sj2.add("Jake").add("John").add("Carl").toString();
// {Jake, John, Carl}
System.out.println(joined2);

You must be a PHP programmer.
Use a + sign.
System.out.println("Your number is " + theNumber + "!");

"+" instead of "."

Use + for string concatenation.
"Your number is " + theNumber + "!"

This should work
public class StackOverflowTest
{
public static void main(String args[])
{
int theNumber = 42;
System.out.println("Your number is " + theNumber + "!");
}
}

For exact concatenation operation of two string please use:
file_names = file_names.concat(file_names1);
In your case use + instead of .

For better performance use str1.concat(str2) where str1 and str2 are string variables.

String.join( delimiter , stringA , stringB , … )
As of Java 8 and later, we can use String.join.
Caveat: You must pass all String or CharSequence objects. So your int variable 42 does not work directly. One alternative is using an object rather than primitive, and then calling toString.
Integer theNumber = 42;
String output =
String // `String` class in Java 8 and later gained the new `join` method.
.join( // Static method on the `String` class.
"" , // Delimiter.
"Your number is " , theNumber.toString() , "!" ) ; // A series of `String` or `CharSequence` objects that you want to join.
) // Returns a `String` object of all the objects joined together separated by the delimiter.
;
Dump to console.
System.out.println( output ) ;
See this code run live at IdeOne.com.

In java concatenate symbol is "+".
If you are trying to concatenate two or three strings while using jdbc then use this:
String u = t1.getString();
String v = t2.getString();
String w = t3.getString();
String X = u + "" + v + "" + w;
st.setString(1, X);
Here "" is used for space only.

In Java, the concatenation symbol is "+", not ".".

"+" not "."
But be careful with String concatenation. Here's a link introducing some thoughts from IBM DeveloperWorks.

You can concatenate Strings using the + operator:
String a="hello ";
String b="world.";
System.out.println(a+b);
Output:
hello world.
That's it

So from the able answer's you might have got the answer for why your snippet is not working. Now I'll add my suggestions on how to do it effectively. This article is a good place where the author speaks about different way to concatenate the string and also given the time comparison results between various results.
Different ways by which Strings could be concatenated in Java
By using + operator (20 + "")
By using concat method in String class
Using StringBuffer
By using StringBuilder
Method 1:
This is a non-recommended way of doing. Why? When you use it with integers and characters you should be explicitly very conscious of transforming the integer to toString() before appending the string or else it would treat the characters to ASCI int's and would perform addition on the top.
String temp = "" + 200 + 'B';
//This is translated internally into,
new StringBuilder().append( "" ).append( 200 ).append('B').toString();
Method 2:
This is the inner concat method's implementation
public String concat(String str) {
int olen = str.length();
if (olen == 0) {
return this;
}
if (coder() == str.coder()) {
byte[] val = this.value;
byte[] oval = str.value;
int len = val.length + oval.length;
byte[] buf = Arrays.copyOf(val, len);
System.arraycopy(oval, 0, buf, val.length, oval.length);
return new String(buf, coder);
}
int len = length();
byte[] buf = StringUTF16.newBytesFor(len + olen);
getBytes(buf, 0, UTF16);
str.getBytes(buf, len, UTF16);
return new String(buf, UTF16);
}
This creates a new buffer each time and copies the old content to the newly allocated buffer. So, this is would be too slow when you do it on more Strings.
Method 3:
This is thread safe and comparatively fast compared to (1) and (2). This uses StringBuilder internally and when it allocates new memory for the buffer (say it's current size is 10) it would increment it's 2*size + 2 (which is 22). So when the array becomes bigger and bigger this would really perform better as it need not allocate buffer size each and every time for every append call.
private int newCapacity(int minCapacity) {
// overflow-conscious code
int oldCapacity = value.length >> coder;
int newCapacity = (oldCapacity << 1) + 2;
if (newCapacity - minCapacity < 0) {
newCapacity = minCapacity;
}
int SAFE_BOUND = MAX_ARRAY_SIZE >> coder;
return (newCapacity <= 0 || SAFE_BOUND - newCapacity < 0)
? hugeCapacity(minCapacity)
: newCapacity;
}
private int hugeCapacity(int minCapacity) {
int SAFE_BOUND = MAX_ARRAY_SIZE >> coder;
int UNSAFE_BOUND = Integer.MAX_VALUE >> coder;
if (UNSAFE_BOUND - minCapacity < 0) { // overflow
throw new OutOfMemoryError();
}
return (minCapacity > SAFE_BOUND)
? minCapacity : SAFE_BOUND;
}
Method 4
StringBuilder would be the fastest one for String concatenation since it's not thread safe. Unless you are very sure that your class which uses this is single ton I would highly recommend not to use this one.
In short, use StringBuffer until you are not sure that your code could be used by multiple threads. If you are damn sure, that your class is singleton then go ahead with StringBuilder for concatenation.

First method: You could use "+" sign for concatenating strings, but this always happens in print.
Another way: The String class includes a method for concatenating two strings: string1.concat(string2);

import com.google.common.base.Joiner;
String delimiter = "";
Joiner.on(delimiter).join(Lists.newArrayList("Your number is ", 47, "!"));
This may be overkill to answer the op's question, but it is good to know about for more complex join operations. This stackoverflow question ranks highly in general google searches in this area, so good to know.

you can use stringbuffer, stringbuilder, and as everyone before me mentioned, "+". I'm not sure how fast "+" is (I think it is the fastest for shorter strings), but for longer I think builder and buffer are about equal (builder is slightly faster because it's not synchronized).

here is an example to read and concatenate 2 string without using 3rd variable:
public class Demo {
public static void main(String args[]) throws Exception {
InputStreamReader r=new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(r);
System.out.println("enter your first string");
String str1 = br.readLine();
System.out.println("enter your second string");
String str2 = br.readLine();
System.out.println("concatenated string is:" + str1 + str2);
}
}

There are multiple ways to do so, but Oracle and IBM say that using +, is a bad practice, because essentially every time you concatenate String, you end up creating additional objects in memory. It will utilize extra space in JVM, and your program may be out of space, or slow down.
Using StringBuilder or StringBuffer is best way to go with it. Please look at Nicolas Fillato's comment above for example related to StringBuffer.
String first = "I eat"; String second = "all the rats.";
System.out.println(first+second);

Using "+" symbol u can concatenate strings.
String a="I";
String b="Love.";
String c="Java.";
System.out.println(a+b+c);

Why string concatenation takes so long time? [duplicate]

This question already has answers here:
StringBuilder vs String concatenation in toString() in Java
(20 answers)
Closed 7 years ago.
I am concatenating a String in a loop but it takes ages, why is that?
for (String object : jsonData) {
counter++;
finalJsonDataStr += object;
}
Variable object is a piece of JSON, up to 70 chars and the loop goes approx 50k times.
I understand some people advice StringBuffer or StringBuilder but this link says, it has no performance improvements: StringBuilder vs String concatenation in toString() in Java

Use a String Builder to append to strings.
When you concatenate, Java is actually creating a new String with the results of the concatenation.
Do it multiple times and you are creating gazillion of strings for nothing.
Try:
StringBuilder sb = new StringBuilder();
for (String object : jsonData) {
counter++;
sb.append(object.toString()); //this does the concatenation internally
//but is very efficient
}
finalJsonDataStr = sb.toString(); //this gives you back the whole string
Remark:
When you do stuff like
myString = "hello " + someStringVariable + " World!" + " My name is " + name;
The compiler is smart enough to replace all that with a single StringBuilder, like:
myString = new StringBuilder("hello ")
.append(someStringVariable)
.append(" World!")
.append(" My name is ")
.append(name).toString();
But for some reason I don't know, it doesn't do it when the concatenation happens inside a loop.

You should use a StringBuffer or a StringBuilder.
When you add Strings with plus, a StringBuilder is created, strings are concatenated and a new String is return with toString() method of the StringBuilder. So image this object creation and string manipulation 50k times. It's much better if you instantiate only one StringBuilder yourself and just append strings...
This answer could be of use to you: concatenation operator (+) vs concat()

Before going to the actual problem, see how internal concatenation works.
String testString ="str"+"ingcon"+"catenation";
If we print the above declared String to console and see, the result is stringconcatenation.Which is correct and the + works fine. Here is out actual question, how does that + symbol did the magic ? ? Is it not a normal mathematical addition of Strings. The below code snippet shows how that code with + actually converts.
StringBuilder compilerGeneratedBuilder = new StringBuilder();
compilerGeneratedBuilder.append("str");
compilerGeneratedBuilder.append("ingcon");
compilerGeneratedBuilder.append("catenation");
String finalString = compilerGeneratedBuilder.toString();
More .....
50K times loop is a descent performance blocker to consider.
In such cases use StringBuilder with append method. Cause concat (+) create a new object every time a new String Builder object. That leads to 50k objects creations.
With single StringBuilder and append method, you can save the time of Objection creation as well as the memory too.

Correct way to use StringBuilder in SQL

I just found some sql query build like this in my project:
return (new StringBuilder("select id1, " + " id2 " + " from " + " table")).toString();
Does this StringBuilder achieve its aim, i.e reducing memory usage?
I doubt that, because in the constructor the '+' (String concat operator) is used. Will that take the same amount of memory as using String like the code below? s I understood, it differs when using StringBuilder.append().
return "select id1, " + " id2 " + " from " + " table";
Are both statements equal in memory usage or not? Please clarify.
Edit:
BTW, it is not my code. Found it in an old project. Also, the query is not so small as the one in my example. :)

The aim of using StringBuilder, i.e reducing memory. Is it achieved?
No, not at all. That code is not using StringBuilder correctly. (I think you've misquoted it, though; surely there aren't quotes around id2 and table?)
Note that the aim (usually) is to reduce memory churn rather than total memory used, to make life a bit easier on the garbage collector.
Will that take memory equal to using String like below?
No, it'll cause more memory churn than just the straight concat you quoted. (Until/unless the JVM optimizer sees that the explicit StringBuilder in the code is unnecessary and optimizes it out, if it can.)
If the author of that code wants to use StringBuilder (there are arguments for, but also against; see note at the end of this answer), better to do it properly (here I'm assuming there aren't actually quotes around id2 and table):
StringBuilder sb = new StringBuilder(some_appropriate_size);
sb.append("select id1, ");
sb.append(id2);
sb.append(" from ");
sb.append(table);
return sb.toString();
Note that I've listed some_appropriate_size in the StringBuilder constructor, so that it starts out with enough capacity for the full content we're going to append. The default size used if you don't specify one is 16 characters, which is usually too small and results in the StringBuilder having to do reallocations to make itself bigger (IIRC, in the Sun/Oracle JDK, it doubles itself [or more, if it knows it needs more to satisfy a specific append] each time it runs out of room).
You may have heard that string concatenation will use a StringBuilder under the covers if compiled with the Sun/Oracle compiler. This is true, it will use one StringBuilder for the overall expression. But it will use the default constructor, which means in the majority of cases, it will have to do a reallocation. It's easier to read, though. Note that this is not true of a series of concatenations. So for instance, this uses one StringBuilder:
return "prefix " + variable1 + " middle " + variable2 + " end";
It roughly translates to:
StringBuilder tmp = new StringBuilder(); // Using default 16 character size
tmp.append("prefix ");
tmp.append(variable1);
tmp.append(" middle ");
tmp.append(variable2);
tmp.append(" end");
return tmp.toString();
So that's okay, although the default constructor and subsequent reallocation(s) isn't ideal, the odds are it's good enough — and the concatenation is a lot more readable.
But that's only for a single expression. Multiple StringBuilders are used for this:
String s;
s = "prefix ";
s += variable1;
s += " middle ";
s += variable2;
s += " end";
return s;
That ends up becoming something like this:
String s;
StringBuilder tmp;
s = "prefix ";
tmp = new StringBuilder();
tmp.append(s);
tmp.append(variable1);
s = tmp.toString();
tmp = new StringBuilder();
tmp.append(s);
tmp.append(" middle ");
s = tmp.toString();
tmp = new StringBuilder();
tmp.append(s);
tmp.append(variable2);
s = tmp.toString();
tmp = new StringBuilder();
tmp.append(s);
tmp.append(" end");
s = tmp.toString();
return s;
...which is pretty ugly.
It's important to remember, though, that in all but a very few cases it doesn't matter and going with readability (which enhances maintainability) is preferred barring a specific performance issue.

When you already have all the "pieces" you wish to append, there is no point in using StringBuilder at all. Using StringBuilder and string concatenation in the same call as per your sample code is even worse.
This would be better:
return "select id1, " + " id2 " + " from " + " table";
In this case, the string concatenation is actually happening at compile-time anyway, so it's equivalent to the even-simpler:
return "select id1, id2 from table";
Using new StringBuilder().append("select id1, ").append(" id2 ")....toString() will actually hinder performance in this case, because it forces the concatenation to be performed at execution time, instead of at compile time. Oops.
If the real code is building a SQL query by including values in the query, then that's another separate issue, which is that you should be using parameterized queries, specifying the values in the parameters rather than in the SQL.
I have an article on String / StringBuffer which I wrote a while ago - before StringBuilder came along. The principles apply to StringBuilder in the same way though.

[[ There are some good answers here but I find that they still are lacking a bit of information. ]]
return (new StringBuilder("select id1, " + " id2 " + " from " + " table"))
.toString();
So as you point out, the example you give is a simplistic but let's analyze it anyway. What happens here is the compiler actually does the + work here because "select id1, " + " id2 " + " from " + " table" are all constants. So this turns into:
return new StringBuilder("select id1, id2 from table").toString();
In this case, obviously, there is no point in using StringBuilder. You might as well do:
// the compiler combines these constant strings
return "select id1, " + " id2 " + " from " + " table";
However, even if you were appending any fields or other non-constants then the compiler would use an internal StringBuilder -- there's no need for you to define one:
// an internal StringBuilder is used here
return "select id1, " + fieldName + " from " + tableName;
Under the covers, this turns into code that is approximately equivalent to:
StringBuilder sb = new StringBuilder("select id1, ");
sb.append(fieldName).append(" from ").append(tableName);
return sb.toString();
Really the only time you need to use StringBuilder directly is when you have conditional code. For example, code that looks like the following is desperate for a StringBuilder:
// 1 StringBuilder used in this line
String query = "select id1, " + fieldName + " from " + tableName;
if (where != null) {
// another StringBuilder used here
query += ' ' + where;
}
The + in the first line uses one StringBuilder instance. Then the += uses another StringBuilder instance. It is more efficient to do:
// choose a good starting size to lower chances of reallocation
StringBuilder sb = new StringBuilder(64);
sb.append("select id1, ").append(fieldName).append(" from ").append(tableName);
// conditional code
if (where != null) {
sb.append(' ').append(where);
}
return sb.toString();
Another time that I use a StringBuilder is when I'm building a string from a number of method calls. Then I can create methods that take a StringBuilder argument:
private void addWhere(StringBuilder sb) {
if (where != null) {
sb.append(' ').append(where);
}
}
When you are using a StringBuilder, you should watch for any usage of + at the same time:
sb.append("select " + fieldName);
That + will cause another internal StringBuilder to be created. This should of course be:
sb.append("select ").append(fieldName);
Lastly, as #T.J.rowder points out, you should always make a guess at the size of the StringBuilder. This will save on the number of char[] objects created when growing the size of the internal buffer.

You are correct in guessing that the aim of using string builder is not achieved, at least not to its full extent.
However, when the compiler sees the expression "select id1, " + " id2 " + " from " + " table" it emits code which actually creates a StringBuilder behind the scenes and appends to it, so the end result is not that bad afterall.
But of course anyone looking at that code is bound to think that it is kind of retarded.

In the code you have posted there would be no advantages, as you are misusing the StringBuilder. You build the same String in both cases. Using StringBuilder you can avoid the + operation on Strings using the append method.
You should use it this way:
return new StringBuilder("select id1, ").append(" id2 ").append(" from ").append(" table").toString();
In Java, the String type is an inmutable sequence of characters, so when you add two Strings the VM creates a new String value with both operands concatenated.
StringBuilder provides a mutable sequence of characters, which you can use to concat different values or variables without creating new String objects, and so it can sometimes be more efficient than working with strings
This provides some useful features, as changing the content of a char sequence passed as parameter inside another method, which you can't do with Strings.
private void addWhereClause(StringBuilder sql, String column, String value) {
//WARNING: only as an example, never append directly a value to a SQL String, or you'll be exposed to SQL Injection
sql.append(" where ").append(column).append(" = ").append(value);
}
More info at http://docs.oracle.com/javase/tutorial/java/data/buffers.html

You could also use MessageFormat too

Why use append() instead of + [duplicate]

This question already has answers here:
Closed 12 years ago.
Possible Duplicate:
Why to use StringBuffer in Java instead of the string concatenation operator
what is the advantage or aim of doing this
int a= 42
StringBuffer sb = new StringBuffer(40);
String s = sb.append("a = ").append(a).append("!").toString();
System.out.println(sb);
result > a = 42!
instead of
int a= 42
String s = "a = " + a + "!";
System.out.println(sb);

In your scenario, I'm not sure there is a difference b/c all of your "+" are on one line (which only creates a String once). In general, though, Strings are immutable objects and are not truly manipulated but rather created and discarded using StringBuffers.
So ultimately, you will have more efficient code if you use StringBuffers (and generally StringBuilders). If you google "String vs. StringBuffer vs. StringBuilder" you can find many articles detailing the statistics.

Efficiency. String concatenation in Java uses StringBuilders in the background anyway, so in some cases you can eke out a bit of efficiency by controlling that yourself.

Just run the code for 10000 time and measure the time. It should be obvious.
Some background-information: String is immutable while StringBuilder is not. So everytime you concatenate a String you have to copy an array.
PS: Sometimes the compiler optimizes things though. Maybe if you make your variable static final it would be just one String internally and no concatenation.

First of all, StringBuffer is synchronized, so you would typically use StringBuilder. + has been reimplemented to use StringBuilder a while ago.
Second, as #Riggy mentioned Java actually does optimize + as long as they occur in a single expression. But if you were to do:
String s = "";
s += a;
s += b;
s += c;
s += d;
Then the effective code would become:
String s ="";
s = new StringBuilder(s).append(a).toString();
s = new StringBuilder(s).append(b).toString();
s = new StringBuilder(s).append(c).toString();
s = new StringBuilder(s).append(d).toString();
which is suboptimal to
String s = new StringBuilder(s).append(a).append(b).append(c).append(d).toString();

Because of compiler optimizations, it may or may not make any difference in your app. You'll have to run comparison speed tests to see.
But before you obsess about performance, get the program working right. "Premature optimization is the root of all evil."

Is there a way to build a Java String using an SLF4J-style formatting function?

I've heard that using StringBuilder is faster than using string concatenation, but I'm tired of wrestling with StringBuilder objects all of the time. I was recently exposed to the SLF4J logging library and I love the "just do the right thing" simplicity of its formatting when compared with String.format. Is there a library out there that would allow me to write something like:
int myInteger = 42;
MyObject myObject = new MyObject(); // Overrides toString()
String result = CoolFormatingLibrary.format("Simple way to format {} and {}",
myInteger, myObject);
Also, is there any reason (including performance but excluding fine-grained control of date and significant digit formatting) why I might want to use String.format over such a library if it does exist?

Although the Accepted answer is good, if (like me) one is interested in exactly Slf4J-style semantics, then the correct solution is to use Slf4J's MessageFormatter
Here is an example usage snippet:
public static String format(String format, Object... params) {
return MessageFormatter.arrayFormat(format, params).getMessage();
}
(Note that this example discards a last argument of type Throwable)

For concatenating strings one time, the old reliable "str" + param + "other str" is perfectly fine (it's actually converted by the compiler into a StringBuilder).
StringBuilders are mainly useful if you have to keep adding things to the string, but you can't get them all into one statement. For example, take a for loop:
String str = "";
for (int i = 0; i < 1000000; i++) {
str += i + " "; // ignoring the last-iteration problem
}
This will run much slower than the equivalent StringBuilder version:
StringBuilder sb = new StringBuilder(); // for extra speed, define the size
for (int i = 0; i < 1000000; i++) {
sb.append(i).append(" ");
}
String str = sb.toString();
But these two are functionally equivalent:
String str = var1 + " " + var2;
String str2 = new StringBuilder().append(var1).append(" ").append(var2).toString();
Having said all that, my actual answer is:
Check out java.text.MessageFormat. Sample code from the Javadocs:
int fileCount = 1273;
String diskName = "MyDisk";
Object[] testArgs = {new Long(fileCount), diskName};
MessageFormat form = new MessageFormat("The disk \"{1}\" contains {0} file(s).");
System.out.println(form.format(testArgs));
Output:
The disk "MyDisk" contains 1,273 file(s).
There is also a static format method which does not require creating a MessageFormat object.
All such libraries will boil down to string concatenation at their most basic level, so there won't be much performance difference from one to another.

Plus it worth bearing in min that String.format() is a bad implementation of sprintf done with regexps, so if you profile your code you will see an patterns and int[] that you were not expecting.
MessageFormat and the slf MessageFormmater are generally faster and allocate less junk