Java multiline string

Question

Coming from Perl  I sure am missing the  here-document  means of creating a multi-line string in source code    string    lt  lt  EOF     create a three-line string text text text EOF   In Java  I have to have cumbersome quotes and plus signs on every line as I concatenate my multiline string from scratch   What are some better alternatives   Define my string in a properties file   Edit  Two answers say StringBuilder append   is preferable to the plus notation   Could anyone elaborate as to why they think so   It doesn t look more preferable to me at all   I m looking for a way around the fact that multiline strings are not a first-class language construct  which means I definitely don t want to replace a first-class language construct  string concatenation with plus  with method calls   Edit  To clarify my question further  I m not concerned about performance at all   I m concerned about maintainability and design issues

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A quite efficient and platform independent solution would be using the system property for line separators and the StringBuilder class to build strings   String separator   System getProperty  line separator    String   lines     Line 1    Line 2                StringBuilder builder   new StringBuilder lines 0    for  int i   1  i  lt  lines length    i          builder append separator  append lines i      String multiLine   builder toString

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I suggest using a utility as suggested by ThomasP  and then link that into your build process   An external file is still present to contain the text  but the file is not read at runtime  The workflow is then    Build a  textfile to java code  utility  amp  check into version control On each build  run the utility against the resource file to create a revised java source The Java source contains a header like class TextBlock      followed by a static string which is auto-generated from the resource file Build the generated java file with the rest of your code

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import org apache commons lang3 StringUtils       String multiline   StringUtils join new String              It was the best of times  it was the worst of times              it was the age of wisdom  it was the age of foolishness            it was the epoch of belief  it was the epoch of incredulity            it was the season of Light  it was the season of Darkness            it was the spring of hope  it was the winter of despair            we had everything before us  we had nothing before us                n

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Define my string in a properties file    Multiline strings aren t allowed in properties files   You can use  n in properties files  but I don t think that is much of a solution in your case

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String newline   System getProperty   line separator    string1   newline   string2   newline   string3   But  the best alternative is to use String format  String multilineString   String format   s n s n s n  line1 line2 line3

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I know this is an old question  however for intersted developers Multi line literals gonna be in  Java12  http   mail openjdk java net pipermail amber-dev 2018-July 003254 html

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A simple option is to edit your java-code with an editor like SciTE  http   www scintilla org SciTEDownload html   which allows you to WRAP the text so that long strings are easily viewed and edited  If you need escape characters you just put them in  By flipping the wrap-option off you can check that your string indeed is still just a long single-line string   But of course  the compiler will tell you too if it isn t   Whether Eclipse or NetBeans support text-wrapping in an editor I don t know  because they have so many options  But if not  that would be a good thing to add

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Java 13 preview      Text Blocks Come to Java     Java 13 delivers long-awaited multiline string by Mala Gupta       With text blocks  Java 13 is making it easier for you to work with multiline string literals  You no longer need to escape the special characters in string literals or use concatenation operators for values that span multiple lines       Text block is defined using three double quotes       as the opening and closing delimiters  The opening delimiter can be followed by zero or more white spaces and a line terminator    Example    String s1        text  text  text

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This is an old thread  but a new quite elegant solution  with only 4 maybe 3 little drawbacks  is to use a custom annotation   Check   http   www adrianwalker org 2011 12 java-multiline-string html  A project inspired from that work is hosted on GitHub    https   github com benelog multiline   Example of Java code   import org adrianwalker multilinestring Multiline      public final class MultilineStringUsage             lt html gt       lt head  gt       lt body gt         lt p gt          Hello lt br  gt          Multiline lt br  gt          World lt br  gt         lt  p gt       lt  body gt     lt  html gt          Multiline   private static String html     public static void main final String   args        System out println html           The drawbacks are    that you have to activate the corresponding  provided  annotation processor   that String variable can not be defined as local variable Check Raw String Literals project where you can define variables as local variables   that String cannot contains other variables as in Visual Basic  Net with XML literal   lt    variable   gt    -  that String literal is delimited by JavaDoc comment         And you probably have to configure Eclipse Intellij-Idea to not reformat automatically your Javadoc comments   One may find this weird  Javadoc comments are not designed to embed anything other than comments   but as this lack of multiline string in Java is really annoying in the end  I find this to be the least worst solution

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In the IntelliJ IDE you just need to type        Then position your cursor inside the quotation marks and paste your string  The IDE will expand it into multiple concatenated lines

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See Java Stringfier  Turns your text into a StringBuilder java block escaping if needed

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The only way I know of is to concatenate multiple lines with plus signs

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This is something that you should never use without thinking about what it s doing   But for one-off scripts I ve used this with great success   Example       System out println S    This is a CRAZY         multiline string with all sorts of strange     characters          Code      From  http   blog efftinge de 2008 10 multi-line-string-literals-in-java html    Takes a comment        and turns everything inside the comment to a string that is returned from S   public static String S         StackTraceElement element   new RuntimeException   getStackTrace   1       String name   element getClassName   replace               java       StringBuilder sb   new StringBuilder        String line   null      InputStream in   classLoader getResourceAsStream name       String s   convertStreamToString in  element getLineNumber         return s substring s indexOf       2  s indexOf               From http   www kodejava org examples 266 html private static String convertStreamToString InputStream is  int lineNum                  To convert the InputStream to String we use the BufferedReader readLine          method  We iterate until the BufferedReader return null which means        there s no more data to read  Each line will appended to a StringBuilder        and returned as String              BufferedReader reader   new BufferedReader new InputStreamReader is        StringBuilder sb   new StringBuilder         String line   null  int i   1      try           while   line   reader readLine       null                if  i    gt   lineNum                    sb append line     n                                  catch  IOException e            e printStackTrace          finally           try               is close              catch  IOException e                e printStackTrace                         return sb toString

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It sounds like you want to do a multiline literal  which does not exist in Java   Your best alternative is going to be strings that are just   d together  Some other options people have mentioned  StringBuilder  String format  String join  would only be preferable if you started with an array of strings   Consider this   String s    It was the best of times  it was the worst of times  n              it was the age of wisdom  it was the age of foolishness  n              it was the epoch of belief  it was the epoch of incredulity  n              it was the season of Light  it was the season of Darkness  n              it was the spring of hope  it was the winter of despair  n              we had everything before us  we had nothing before us     Versus StringBuilder   String s   new StringBuilder               append  It was the best of times  it was the worst of times  n               append  it was the age of wisdom  it was the age of foolishness  n               append  it was the epoch of belief  it was the epoch of incredulity  n               append  it was the season of Light  it was the season of Darkness  n               append  it was the spring of hope  it was the winter of despair  n               append  we had everything before us  we had nothing before us               toString      Versus String format     String s   String format   s n s n s n s n s n s              It was the best of times  it was the worst of times               it was the age of wisdom  it was the age of foolishness               it was the epoch of belief  it was the epoch of incredulity               it was the season of Light  it was the season of Darkness               it was the spring of hope  it was the winter of despair               we had everything before us  we had nothing before us       Versus Java8 String join     String s   String join   n              It was the best of times  it was the worst of times               it was the age of wisdom  it was the age of foolishness               it was the epoch of belief  it was the epoch of incredulity               it was the season of Light  it was the season of Darkness               it was the spring of hope  it was the winter of despair               we had everything before us  we had nothing before us       If you want the newline for your particular system  you either need to use System lineSeparator    or you can use  n in String format   Another option is to put the resource in a text file  and just read the contents of that file  This would be preferable for very large strings to avoid unnecessarily bloating your class files

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Using this library  https   github com alessio-santacroce multiline-string-literals  it is possible to write things like this  System out println newString          Wow  we finally have       multiline strings in       Java  HOOO          Very nice and easy  but works only for unit tests

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Actually  the following is the cleanest implementation I have seen so far   It uses an annotation to convert a comment into a string variable            lt html gt       lt head  gt       lt body gt         lt p gt          Hello lt br  gt          Multiline lt br  gt          World lt br  gt         lt  p gt       lt  body gt     lt  html gt          Multiline   private static String html    So  the end result is that the variable html contains the multiline string   No quotes  no pluses  no commas  just pure string   This solution is available at the following URL    http   www adrianwalker org 2011 12 java-multiline-string html  Hope that helps

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I got a bit annoyed with reading that multiline syntax is indeed been planned for jdk7  after about how many decades of java existence    Funnily  there is not even yet a readAll   function for reading the complete contents of a file  from jdk7 only  huhh   so the code below reads single lines          MakeMultiline v1 0  2010  - Free to use and copy     Small gadget to turn text blobs into one java string literal    doing the split in lines  adding  n at each end and enclosing   in double quotes   Does escape quotes encountered in the text blob     Useful for working around missing multiline string syntax in java   prior jdk7  Use with        java MakeMultiline          or      java MakeMultiline        mytextfile txt     import java io     class MakeMultiline     public static void main String   args        try            args 0   indent          args 1   filename to read  optional  stdin if not given           Beware the nmb of newlines at the end when using stdin         String indent    args length   0   args 0               FileReader fr   null  BufferedReader br        if  args length   1            fr    new FileReader args 1    br   new BufferedReader fr           else           br   new BufferedReader new InputStreamReader System in            String s  String res             while  s   br readLine       null            if  res length     0  res        n           res    indent          s replace                    n                   br close    if  fr    null  fr close          System out println res                   catch Exception e          System out println  Exception      e                 This was the quickest solution for me   2010-01-27

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Late model JAVA has optimizations for   with constant strings  employs a StringBuffer behind the scenes  so you do not want to clutter your code with it   It points to a JAVA oversight  that it does not resemble ANSI C in the automatic concatenation of double quoted strings with only white space between them  e g    const char usage     n   Usage  xxxx  lt options gt  n    n   Removes your options as designated by the required parameter  lt options gt   n   which must be one of the following strings  n     love n     sex n     drugs n     rockandroll n    n      I would love to have a multi-line character array constant where embedded linefeeds are honored  so I can present the block without any clutter  e g    String Query     SELECT     some column      another column   FROM       one table a     JOIN       another table b     ON    a id   b id       AND a role code   b role code   WHERE a dept    sales      AND b sales quote  gt  1000   Order BY 1  2       To get this  one needs to beat on the JAVA gods

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An alternative I haven t seen as answer yet is the java io PrintWriter   StringWriter stringWriter   new StringWriter    PrintWriter writer   new PrintWriter stringWriter   writer println  It was the best of times  it was the worst of times    writer println  it was the age of wisdom  it was the age of foolishness     writer println  it was the epoch of belief  it was the epoch of incredulity     writer println  it was the season of Light  it was the season of Darkness     writer println  it was the spring of hope  it was the winter of despair     writer println  we had everything before us  we had nothing before us    String string   stringWriter toString      Also the fact that java io BufferedWriter has a newLine   method is unmentioned

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Another option may be to store long strings in an external file and read the file into a string

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I see at least one case where it should be avoided to use external files for long strings   if these long string are expected values in an unit-test file  because I think the tests should always be written in a way that they don t rely on any external resource

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In Eclipse if you turn on the option  Escape text when pasting into a string literal   in Preferences   Java   Editor   Typing  and paste a multi-lined string whithin quotes  it will automatically add   and  n    for all your lines   String str    paste your text here

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JEP 378  Text Blocks covers this functionality and is included in JDK 15  It first appeared as JEP 355  Text Blocks  Preview  in JDK 13 and JEP 368  Text Blocks  Second Preview  in JDK 14 and can be enabled in these versions with the       enable   preview javac option  The syntax allows to write something like  String s    quot  quot  quot             text            text            text             quot  quot  quot    Previous to this JEP  in JDK 12  JEP 326  Raw String Literals aimed to implement a similar feature  but it was eventually withdrawn   Please note  This was intended to be a preview language feature in JDK 12  but it was withdrawn and did not appear in JDK 12  It was superseded by Text Blocks  JEP 355  in JDK 13

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Sadly  Java does not have multi-line string literals  You either have to concatenate string literals  using   or StringBuilder being the two most common approaches to this  or read the string in from a separate file   For large multi-line string literals I d be inclined to use a separate file and read it in using getResourceAsStream    a method of the Class class   This makes it easy to find the file as you don t have to worry about the current directory versus where your code was installed  It also makes packaging easier  because you can actually store the file in your jar file   Suppose you re in a class called Foo  Just do something like this   Reader r   new InputStreamReader Foo class getResourceAsStream  filename     UTF-8    String s   Utils readAll r     The one other annoyance is that Java doesn t have a standard  read all of the text from this Reader into a String  method  It s pretty easy to write though   public static String readAll Reader input        StringBuilder sb   new StringBuilder        char   buffer   new char 4096       int charsRead      while   charsRead   input read buffer    gt   0            sb append buffer  0  charsRead             input close        return sb toString

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If you define your strings in a properties file it ll look much worse  IIRC  it ll look like   string text u000atext u000atext u000a   Generally it s a reasonable idea to not embed large strings in to source  You might want to load them as resources  perhaps in XML or a readable text format  The text files can be either read at runtime or compiled into Java source  If you end up placing them in the source  I suggest putting the   at the front and omitting unnecessary new lines   final String text            text         text         text      If you do have new lines  you might want some of join or formatting method   final String text   join   r n        text        text        text

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One good option   import static some Util         public class Java            public static void main String   args                 String sql                     Select   from java                  join some on                   group by                                      System out println sql                          public class Util            public static String   String    sql               return String join System getProperty  line separator   sql

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I sometimes use a parallel groovy class just to act as a bag of strings  The java class here  public class Test       public static void main String   args            System out println TestStrings json1              consume    parse json           And the coveted multiline strings here in TestStrings groovy  class TestStrings       public static String json1                      name    Fakeer s Json            age  100           messages    msg 1   msg 2   msg 3                 Of course this is for static strings only  If I have to insert variables in the text I will just change the entire file to groovy  Just maintain strong-typing practices and it can be pulled off

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Since Java does not  yet  native support multi-line strings  the only way for now is to hack around it using one of the aforementioned techniques  I built the following Python script using some of the tricks mentioned above   import sys import string import os  print  new String   for line in sys stdin      one   string replace line              rstrip os linesep      print           one        print       Put that in a file named javastringify py and your string in a file mystring txt and run it as follows   cat mystring txt   python javastringify py   You can then copy the output and paste it into your editor    Modify this as needed to handle any special cases but this works for my needs  Hope this helps

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It may seem a little crazy  but since heredocs are syntactic sugar over one-line declarations with linebreaks escaped  one could write pre-processor for Java files that would change heredocs into single-liners during preprocessing    It would require writing proper plugins for preprocessing files before compilation phase  for ant maven build  and a plugin to IDE    From an ideological point of view  it differs nothing from f g   generics   that is also a kind of pre-processed syntactic sugar over casting   It s  however  a lot of work  so I would at your place just use  properties files

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String join  Java 8 added a new static method to java lang String which offers a slightly better alternative   String join      CharSequence delimiter        CharSequence    elements    Using it   String s   String join      System getProperty  line separator         First line         Second line         The rest         And the last

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Java15 now supports triple-quoted strings a la Python

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Use Properties loadFromXML InputStream   There s no need for external libs   Better than a messy code  since maintainability and design are your concern   it is preferable not to use long strings   Start by reading xml properties    InputStream fileIS   YourClass class getResourceAsStream  MultiLine xml     Properties prop   new Properies     prop loadFromXML fileIS      then you can use your multiline string in a more maintainable way     static final String UNIQUE MEANINGFUL KEY    Super Duper UNIQUE Key   prop getProperty UNIQUE MEANINGFUL KEY       n    MEGA n   LONG n        MultiLine xml  gets located in the same folder YourClass    lt  xml version  1 0  encoding  UTF-8   gt   lt  DOCTYPE properties SYSTEM  http   java sun com dtd properties dtd  gt    lt properties gt       lt entry key  Super Duper UNIQUE Key  gt         MEGA        LONG        MULTILINE      lt  entry gt   lt  properties gt    PS   You can use  lt   CDATA           gt  for xml-like string

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Pluses are converted to StringBuilder append  except when both strings are constants so the compiler can combine them at compile time  At least  that s how it is in Sun s compiler  and I would suspect most if not all other compilers would do the same   So   String a  Hello   String b  Goodbye   String c a b    normally generates exactly the same code as   String a  Hello   String b  Goodbye   StringBuilder temp new StringBuilder    temp append a  append b   String c temp toString      On the other hand   String c  Hello   Goodbye     is the same as   String c  HelloGoodbye     That is  there s no penalty in breaking your string literals across multiple lines with plus signs for readability

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One small trick  Using this I inject javascritp in a dynamically created HTML page   StringBuilder builder   new StringBuilder     public String getString         return builder toString      private DropdownContent   String a        builder append a       return this     public String funct showhide        return        function slidedown showHide boxId                        if  slidedown direction boxId  slidedown direction boxId    1            if  slideDownInitHeight boxId  slideDownInitHeight boxId    0            if slideDownInitHeight boxId   0 slidedown direction boxId  slidedownSpeed             else slidedown direction boxId    slidedownSpeed -1            slidedownContentBox   document getElementById boxId             var subDivs   slidedownContentBox getElementsByTagName  DIV              for var no 0 no lt subDivs length no                if subDivs no  className   dhtmlgoodies content  slidedownContent   subDivs no                         contentHeight   slidedownContent offsetHeight            slidedownContentBox style visibility  visible             slidedownActive   true            slidedown showHide start slidedownContentBox slidedownContent                 getString

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Two answers to this question    In you want to stick to pure Java  with Java 14 being released in March 2020  you can leverage the JEP 368 - Text Blocks  in Second Preview mode  Actually the feature is in preview mode in other releases  at least 13 has it   I created and example set here  While this feature is useful  it can be easily abused  Remember that Java requires compilation - having large character arrays in your code can be an easy way to shoot yourself in the leg  if you want a quick change  you will need recompilation - that toolset might not be available to the guy operating your application     In my experience  it is advisable to keep large strings  and generally strings that could should be altered at runtime by app operators  in configuration files   Summary  use text blocks responsibly

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With JDK 12 early access build   12  one can now use multiline strings in Java as follows    String multiLine    First line     Second line with indentation Third line and so on         the formatting as desired System out println multiLine     and this results in the following output    First line     Second line with indentation Third line and so on       Edit  Postponed to java 13

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If you like google s guava as much as I do  it can give a fairly clean representation and a nice  easy way to not hardcode your newline characters too   String out   Joiner on newline  join ImmutableList of       line1        line2        line3

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You can concatenate your appends in a separate method like   public static String multilineString String    lines      StringBuilder sb   new StringBuilder       for String s   lines        sb append s        sb append    n            return sb toString        Either way  prefer StringBuilder to the plus notation

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Stephen Colebourne has created a proposal for adding multi-line strings in Java 7   Also  Groovy already has support for multi-line strings

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Java 13 and beyond Multiline Strings are now supported in Java via Text Blocks  In Java 13 and 14  this feature requires you to set the       enable   preview option when building and running your project  In Java 15 and later  this option is no longer required as Text Blocks have become a standard feature  Check out this Java documentation for more details  Now  prior to Java 13  this is how you d write a query  List lt Tuple gt  posts   entityManager  createNativeQuery       quot SELECT   n quot         quot FROM   n quot         quot     SELECT    n quot         quot            dense rank   OVER   n quot         quot                ORDER BY   quot p created on  quot     quot p id  quot  n quot         quot              rank n quot         quot     FROM   n quot         quot         SELECT p id AS   quot p id  quot   n quot         quot                p created on AS   quot p created on  quot   n quot         quot                p title AS   quot p title  quot   n quot         quot                pc id as   quot pc id  quot   n quot         quot                pc created on AS   quot pc created on  quot   n quot         quot                pc review AS   quot pc review  quot   n quot         quot                pc post id AS   quot pc post id  quot  n quot         quot         FROM post p n quot         quot         LEFT JOIN post comment pc ON p id   pc post id n quot         quot         WHERE p title LIKE  titlePattern n quot         quot         ORDER BY p created on n quot         quot       p pc n quot         quot   p pc r n quot         quot WHERE p pc r rank  lt    rank n quot       Tuple class   setParameter  quot titlePattern quot    quot High-Performance Java Persistence   quot    setParameter  quot rank quot   5   getResultList     Thanks to Java 13 Text Blocks  you can rewrite this query as follows  List lt Tuple gt  posts   entityManager  createNativeQuery  quot  quot  quot      SELECT       FROM           SELECT                   dense rank   OVER                      ORDER BY  quot p created on quot    quot p id quot                   rank         FROM               SELECT p id AS  quot p id quot                      p created on AS  quot p created on quot                      p title AS  quot p title quot                      pc id as  quot pc id quot                      pc created on AS  quot pc created on quot                      pc review AS  quot pc review quot                      pc post id AS  quot pc post id quot              FROM post p             LEFT JOIN post comment pc ON p id   pc post id             WHERE p title LIKE  titlePattern             ORDER BY p created on           p pc       p pc r     WHERE p pc r rank  lt    rank      quot  quot  quot       Tuple class   setParameter  quot titlePattern quot    quot High-Performance Java Persistence   quot    setParameter  quot rank quot   5   getResultList     Much more readable  right  IDE support IntelliJ IDEA provides support for transforming legacy String concatenation blocks to the new multiline String format   JSON  HTML  XML The multiline String is especially useful when writing JSON  HTML  or XML  Consider this example using String concatenation to build a JSON string literal  entityManager persist      new Book        setId 1L       setIsbn  quot 978-9730228236 quot        setProperties           quot   quot             quot      quot title  quot     quot High-Performance Java Persistence  quot   quot             quot      quot author  quot     quot Vlad Mihalcea  quot   quot             quot      quot publisher  quot     quot Amazon  quot   quot             quot      quot price  quot   44 99  quot             quot      quot reviews  quot     quot             quot          quot             quot              quot reviewer  quot     quot Cristiano  quot    quot             quot              quot review  quot     quot Excellent book to understand Java Persistence  quot    quot             quot              quot date  quot     quot 2017-11-14  quot    quot             quot              quot rating  quot   5 quot             quot           quot             quot          quot             quot              quot reviewer  quot     quot T W  quot    quot             quot              quot review  quot     quot The best JPA ORM book out there  quot    quot             quot              quot date  quot     quot 2019-01-27  quot    quot             quot              quot rating  quot   5 quot             quot           quot             quot          quot             quot              quot reviewer  quot     quot Shaikh  quot    quot             quot              quot review  quot     quot The most informative book  quot    quot             quot              quot date  quot     quot 2016-12-24  quot    quot             quot              quot rating  quot   4 quot             quot          quot             quot      quot             quot   quot            You can barely read the JSON due to the escaping characters and the abundance of double quotes and plus signs  With Java Text Blocks  the JSON object can be written like this  entityManager persist      new Book        setId 1L       setIsbn  quot 978-9730228236 quot        setProperties  quot  quot  quot                        quot title quot    quot High-Performance Java Persistence quot               quot author quot    quot Vlad Mihalcea quot               quot publisher quot    quot Amazon quot               quot price quot   44 99              quot reviews quot                                          quot reviewer quot    quot Cristiano quot                       quot review quot    quot Excellent book to understand Java Persistence quot                       quot date quot    quot 2017-11-14 quot                       quot rating quot   5                                                        quot reviewer quot    quot T W quot                       quot review quot    quot The best JPA ORM book out there quot                       quot date quot    quot 2019-01-27 quot                       quot rating quot   5                                                        quot reviewer quot    quot Shaikh quot                       quot review quot    quot The most informative book quot                       quot date quot    quot 2016-12-24 quot                       quot rating quot   4                                                  quot  quot  quot            Ever since I used C  in 2004  I ve been wanting to have this feature in Java  and now we finally have it

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You may use scala-code  which is compatible to java  and allows multiline-Strings enclosed with       package foobar object SWrap     def bar      John said   This is   a test   a bloody test    my dear   and closed the door           note the quotes inside the string  and from java   String s2   foobar SWrap bar       Whether this is more comfortable        Another approach  if you often handle long text  which should be placed in your sourcecode  might be a script  which takes the text from an external file  and wrappes it as a multiline-java-String like this    sed  1s   String s       2  s    t     2  s       file  gt  file java   so that you may cut-and-paste it easily into your source

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When a long series of   are used  only one StringBuilder is created  unless the String is determined at compile time in which case no StringBuilder is used   The only time StringBuilder is more efficient is when multiple statements are used to construct the String   String a    a n   String b    b n   String c    c n   String d    d n    String abcd   a   b   c   d  System out println abcd    String abcd2    a n             b n             c n             d n   System out println abcd2     Note  Only one StringBuilder is created     Code     0    ldc      2    String a n    2    astore 1    3    ldc      3    String b n    5    astore 2    6    ldc      4    String c n    8    astore 3    9    ldc      5    String d n    11   astore  4    13   new      6    class java lang StringBuilder    16   dup    17   invokespecial    7    Method java lang StringBuilder   lt init gt     V    20   aload 1    21   invokevirtual    8    Method java lang StringBuilder append  Ljava lang String  Ljava lang StringBuilder     24   aload 2    25   invokevirtual    8    Method java lang StringBuilder append  Ljava lang String  Ljava lang StringBuilder     28   aload 3    29   invokevirtual    8    Method java lang StringBuilder append  Ljava lang String  Ljava lang StringBuilder     32   aload   4    34   invokevirtual    8    Method java lang StringBuilder append  Ljava lang String  Ljava lang StringBuilder     37   invokevirtual    9    Method java lang StringBuilder toString   Ljava lang String     40   astore  5    42   getstatic        10    Field java lang System out Ljava io PrintStream     45   aload   5    47   invokevirtual    11    Method java io PrintStream println  Ljava lang String  V    50   ldc      12    String a nb nc nd n    52   astore  6    54   getstatic        10    Field java lang System out Ljava io PrintStream     57   aload   6    59   invokevirtual    11    Method java io PrintStream println  Ljava lang String  V    62   return      To clarify my question further  I m not concerned about performance at all  I m concerned about maintainability and design issues    Make it as clear and simple as you can

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It s not entirely clear from the question if author is interested in working with some sort of formatted large strings that need to have some dynamic values  but if that s the case a templating engine like StringTemplate  http   www stringtemplate org   might be very useful   A simple sample of the code that uses StringTemplate is below  The actual template   Hello   lt  name     could be loaded from an external plain text file  All indentation in the template will be preserved  and no escaping is necessary   import org stringtemplate v4       public class Hello           public static void main String   args                    ST hello   new ST  Hello   lt name gt                     hello add  name    World                    System out println hello render                   P S  It s always a good idea to remove large chunks of text from source code for readability and localization purposes

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