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diff --git a/challenge-266/luca-ferrari/pljava/src/main/java/Task1.java b/challenge-266/luca-ferrari/pljava/src/main/java/Task1.java
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+
+
+
+package PWC266;
+
+/**
+ * PL/Java implementation for PWC 266
+ * Task 1
+ * See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-266>
+ *
+ *
+ * To compile on the local machine:
+
+ $ export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64/  # if not already set
+ $ mvn clean build
+ $ scp target/PWC266-1.jar  luca@rachel:/tmp
+
+
+ * To install into PostgreSQL execute:
+
+ select sqlj.install_jar( 'file:///tmp/PWC266-1.jar', 'PWC266', true );
+ select sqlj.set_classpath( 'public', 'PWC266' );
+
+ select pwc266.task2_pljava();
+
+ and then to redeploy:
+
+ select sqlj.replace_jar( 'file:///tmp/PWC266-1.jar', 'PWC266', true );
+
+*/
+
+import org.postgresql.pljava.*;
+import org.postgresql.pljava.annotation.Function;
+import static org.postgresql.pljava.annotation.Function.Effects.IMMUTABLE;
+import static org.postgresql.pljava.annotation.Function.OnNullInput.RETURNS_NULL;
+
+import java.util.*;
+import java.util.stream.*;
+import java.sql.SQLException;
+import java.util.logging.*;
+import java.sql.ResultSet;
+import java.sql.Date;
+
+public class Task1 {
+
+    private final static Logger logger = Logger.getAnonymousLogger();
+
+    @Function( schema = "pwc266",
+	       onNullInput = RETURNS_NULL,
+	       effects = IMMUTABLE )
+    public static final String[] task1_pljava( String left, String right ) throws SQLException {
+	logger.log( Level.INFO, "Entering pwc266.task1_pljava" );
+
+	Map<String, Integer> bag_left  = new HashMap<String, Integer>();
+	Map<String, Integer> bag_right = new HashMap<String, Integer>();
+
+	classify( bag_left, left );
+	classify( bag_right, right );
+
+
+	List<String> words = deduplicate( bag_left, bag_right );
+	String returning[] = new String[ words.size() ];
+	int i = 0;
+	for ( String word : words )
+	    returning[ i++ ] = word;
+
+	return returning;
+    }
+
+
+    private static final List<String> deduplicate( Map<String, Integer> bag_left,
+						   Map<String, Integer> bag_right ) {
+
+	List<String> words = new LinkedList<String>();
+
+	for ( String word : bag_left.keySet() ) {
+	    if ( bag_left.get( word ) == 1 && ! bag_right.containsKey( word ) )
+		words.add( word );
+	}
+
+	for ( String word : bag_right.keySet() ) {
+	    if ( bag_right.get( word ) == 1 && ! bag_left.containsKey( word ) )
+		words.add( word );
+	}
+
+	return words;
+    }
+
+    private static final void classify( Map<String, Integer> bag, String sentence ) {
+	for ( String word : sentence.split( "\\W+" ) ) {
+	    word = word.toLowerCase();
+	    int count = 1;
+	    if ( bag.containsKey( word ) )
+		count += bag.get( word );
+
+	    bag.put( word, count );
+	}
+    }
+}