Tag Archives: local-variable-type-inference

java is smart – using var

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I was working on some code and seeing how many local variables I could substitute with var. I was a little surprised to learn that the below compiles. It makes sense to me that mags is good because the type is there. It’s cool that years and sorted can infer the type of Integer as well.

package lists;

import java.util.*;

public class Magazines {

    public static void main(String[] args) {
        var mags = new HashMap<String, Integer>();
        mags.put("People", 1974);
        mags.put("Readers Digest", 1922);
        mags.put("The Economist", 1843);

        var years = mags.values();

        var sorted = new ArrayList<>(years);
        Collections.sort(sorted);

        int first = sorted.get(0);
        System.out.println(first);
    }
}