XMLEscaper.java

package util;

import java.text.CharacterIterator;
import java.text.StringCharacterIterator;

public class XMLEscaper {
    public static final String[] ESCAPED_CHAR = {"&", "'", "\"", "<", ">"};

    public String escape(String aText) {
        if (aText == null) return null;

        StringBuilder result = new StringBuilder();
        StringCharacterIterator iterator = new StringCharacterIterator(aText);
        char character = iterator.current();
        while (character != CharacterIterator.DONE) {
            if (character == '<') {
                result.append("&lt;");
            } else if (character == '>') {
                result.append("&gt;");
            } else if (character == '&') {
                result.append("&amp;");
            } else if (character == '\"') {
                result.append("&quot;");
            } else if (character == '\'') {
                result.append("&apos;");
            } else {
                result.append(character);
            }
            character = iterator.next();
        }
        return result.toString();
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("List of escaped characters: ");
        for (String escChar : ESCAPED_CHAR) {
            sb.append(escChar).append(" ");
        }
        return sb.toString();
    }
}

XMLEscaperTest.java

package util;

import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.assertEquals;

public class XMLEscaperTest {
    private XMLEscaper testInstance;

    @Before
    public void setUp() {
        testInstance = new XMLEscaper();
    }

    @Test
    public final void escape() {
        String test = "abra\'< cadabra\"> &";
        String result = testInstance.escape(test);
        String expected = "abra&apos;&lt; cadabra&quot;&gt; &amp;";
        assertEquals(expected, result);
    }
}