lots of exercises in java... from https://github.com/exercism/java

DiamondPrinter.java 205B

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  1. import java.util.List;
  2. class DiamondPrinter {
  3. List<String> printToList(char a) {
  4. throw new UnsupportedOperationException("Delete this statement and write your own implementation.");
  5. }
  6. }