How to convert a String to CharSequence

Question

How to convert String to CharSequence in Java

User · Answer

CharSequence is an interface and String is its one of the implementations other than StringBuilder, StringBuffer and many other.

So, just as you use InterfaceName i = new ItsImplementation(), you can use CharSequence cs = new String("string") or simply CharSequence cs = "string";

User · Answer

That s a good question  You may get into troubles if you invoke API that uses generics and want to assign or return that result with a different subtype of the generic type  Java 8 helps to transform      List lt String gt  input   new LinkedList lt  gt  Arrays asList  quot a quot    quot b quot    quot c quot         List lt CharSequence gt  result             result   input      lt -- Type mismatch  cannot convert from List lt String gt  to List lt CharSequence gt      result   input stream   collect Collectors toList              System out println result

User · Answer

Straight answer   String s    Hello World        String   gt  CharSequence conversion   CharSequence cs   s      String is already a CharSequence   CharSequence is an interface  and the String class implements CharSequence

User · Answer

You can use   CharSequence   cs   String     String to CharSequence

User · Answer

Attempting to provide some  possible  context for OP s question by posting my own trouble  I m working in Scala  but the error messages I m getting all reference Java types  and the error message reads a lot like the compiler complaining that CharSequence is not a String   I confirmed in the source code that String implements the CharSequence interface  but the error message draws attention to the difference between String and CharSequence while hiding the real source of the trouble   scala gt  cols res8  Iterable String    List Item  a  b   scala gt  val header   String join      cols   lt console gt  13  error  overloaded method value join with alternatives     x 1  CharSequence x 2  java lang Iterable    lt   CharSequence  String  lt and gt     x 1  CharSequence x 2  CharSequence  String  cannot be applied to  String  Iterable String          val header   String join      cols    I was able to fix this problem with the realization that the problem wasn t String   CharSequence  but rather a mismatch between java lang Iterable and Scala s built-in Iterable   scala gt  val header   String join      coll      header  String   Item a b   My particular problem can also be solved via the answers at Scala  join an iterable of strings  In summary  OP and others who come across similar problems should parse the error messages very closely and see what other type conversions might be involved

User · Answer

Since String IS-A CharSequence  you can pass a String wherever you need a CharSequence  or assign a String to a CharSequence   CharSequence cs    string   String s   cs toString    foo s      prints  string   public void foo CharSequence cs       System out println cs       If you want to convert a CharSequence to a String  just use the toString method that must be implemented by every concrete implementation of CharSequence   Hope it helps

[java] How to convert a String to CharSequence?

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