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How to print a specific instance of an object using toString

How do I print and a specific instance of an object using toString?

So basically the user enters information. based on the input, it will either be stored in instance A or instance B. Both instances A and B are subclasses, with overriding toString methods. so the user's input is stored in an array. How can I make it so that all inputs that were instance of A are printed?

This is the code I have and it doesn't work.

public static void printA(ABC[] inputs)
    {
        for(int i = 0; i < inputs.length; i++)
        {   
            if(inputs[i] instanceof A)
            {
                JOptionPane.showMessageDialog(null, inputs.toString());
            }
        }
    }
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2 answers


you just need

JOptionPane.showMessageDialog(null, inputs[i].toString());


Because you are array.toString()

not trying to show the value you want.

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You are iterating inputs

, but testing clients

. This is why I prefer to use a loop for-each

, and I suggest you use StringBuilder

to create one message and then display it once. Something like,

public static void printA(ABC[] inputs) {
    StringBuilder sb = new StringBuilder();
    for (ABC input : inputs) {
        if (input instanceof A) {
            sb.append(input).append(System.lineSeparator());
        }
    }
    JOptionPane.showMessageDialog(null, sb.toString().trim());
}

Edit



The result you get ("LClient; @ 20d9896e") is what you display inputs.toString()

. Array does not override toString()

, you can use Arrays.toString(Object[])

for example

String msg = Arrays.toString(inputs);

But you will get all the elements in the array. Also, make sure to Client

override toString()

.

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