Best approach to converting Boolean object to string in java

Question

I am trying to convert boolean to string type     Boolean b   true  String str   String valueOf b     or  Boolean b   true  String str   Boolean toString b     which one of above would be more efficient

User · Answer

Depends on what you mean by  efficient   Performance-wise both versions are the same as its the same bytecode       javap exe -c java lang String   grep -A 10  valueOf boolean     public static java lang String valueOf boolean       Code         0  iload 0        1  ifeq          9        4  ldc            14                    String true        6  goto          11        9  ldc            10                    String false       11  areturn       javap exe -c java lang Boolean   grep -A 10  toString boolean     public static java lang String toString boolean       Code         0  iload 0        1  ifeq          9        4  ldc            3                     String true        6  goto          11        9  ldc            2                     String false       11  areturn

User · Answer

If you are sure that your value is not null you can use third option which is  String str3   b toString      and its code looks like  public String toString         return value    true     false         If you want to be null-safe use String valueOf b  which code looks like  public static String valueOf Object obj        return  obj    null     null    obj toString        so as you see it will first test for null and later invoke toString   method on your object      Calling Boolean toString b  will invoke   public static String toString boolean b        return b    true     false       which is little slower than b toString   since JVM needs to first unbox Boolean to boolean which will be passed as argument to Boolean toString       while b toString   reuses private boolean value field in Boolean object which holds its state

User · Answer

If you see implementation of both the method  they look same   String valueOf b   public static String valueOf boolean b            return b    true     false           Boolean toString b   public static String toString boolean b            return b    true     false           So both the methods are equally efficient

User · Answer

If you re looking for a quick way to do this  for example debugging  you can simply concatenate an empty string on to the boolean   System out println b        However  I strongly recommend using another method for production usage  This is a simple quick solution which is useful for debugging

User · Answer

public class Sandbox                    param args the command line arguments             public static void main String   args            Boolean b   true          boolean z   false          echo  b           echo  z           echo   Value of b      b    nValue of z      z              public static void echo Object obj           System out println obj                Result -------------- true false Value of b  true Value of z  false --------------

User · Answer

I don t think there would be any significant performance difference between them  but I would prefer the 1st way   If you have a Boolean reference  Boolean toString boolean  will throw NullPointerException if your reference is null  As the reference is unboxed to boolean before being passed to the method   While  String valueOf   method as the source code shows  does the explicit null check   public static String valueOf Object obj        return  obj    null     null    obj toString        Just test this code   Boolean b   null   System out println String valueOf b          Prints null System out println Boolean toString b        Throws NPE     For primitive boolean  there is no difference

User · Answer

If this is for the purpose of getting a constant  true  value  rather than  True  or  TRUE   you can use this   Boolean TRUE toString    Boolean FALSE toString

[java] Best approach to converting Boolean object to string in java

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