Get String from Object which is a char array (NOT an Object[])

Question

This is not a duplicate, please read the question and understand that I have an Object (not a char[], not an Object[], but an Object)

public String getStringFromObject(Object o){
  // What do I do here to get a String?  o is actually a char[]
}

I have a java Object that represents a character array:

I get passed an Object cred into a method

L.info("Credentials component type is {} and is array -> {}", 
       cred.getClass().getComponentType(), cred.getClass().isArray());

This prints: Token's credentials are: [s, d, f] and type is [C

How do I get this into a String? I can't figure out how to cast the Object to any kind of [] array. If it was Object[] to start with it would not be a problem.

[C means it's a char[] so cast to that. Then call the String(char[]) constructor. — Thomas
– Thomas, Commented Jun 13, 2016 at 16:26
The output seems from a different log statement. Are you sure you posted the right one? — M A
– M A, Commented Jun 13, 2016 at 16:27
Possible duplicate of How to convert a char array back to a string? — user3838784
– user3838784, Commented Jun 13, 2016 at 16:27
Why are you passing in an Object if it is a char[]? Why not just pass the character array? (I'm mainly asking this for my own selfish education). Is this for study? — David
– David, Commented Jun 13, 2016 at 16:44
Why you are doing it , when you can directly convert Character array to String? Help us — Ravi Rajput
– Ravi Rajput, Commented Jun 13, 2016 at 17:42

Davide Lorenzo MARINO · Accepted Answer · 2016-06-13 16:47:48Z

4

If you have a char[] and you want to convert it to a String simply use the constructor

public String(char[] value)

From javadoc:

Allocates a new String so that it represents the sequence of characters currently contained in the character array argument. The contents of the character array are copied; subsequent modification of the character array does not affect the newly created string.

Note

If you have an Object that is a char[] here is what you have:

char[] x = ....;
Object objectIsACharArray = x;
String s = new String((char[]) x);

If the Object is not a char[] but is something that represent or hold a char array you need a custom code to convert it to a String.

edited Jun 13, 2016 at 16:47

answered Jun 13, 2016 at 16:27

Davide Lorenzo MARINO

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2 Comments

mikeb Over a year ago

You didn't understand the question. I have an Object.

bcsb1001 Over a year ago

There is no String constructor that takes an Object. You can't just declare x as Object then call new String(x), for this reason. Casting is an option here though, I believe.

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