Java Utililty Methods Map Merge

final Map<String, T> res = new HashMap<>();
res.putAll(map1);
res.putAll(map2);
return res;

for (Map.Entry<T1, T2> entry : second.entrySet()) {
    T1 key = entry.getKey();
    if (!first.containsKey(key)) {
        first.put(key, entry.getValue());
return first;

for (Entry<? extends TKey, ? extends Integer> entry2 : source.entrySet()) {
    TKey key2 = entry2.getKey();
    int val2 = entry2.getValue();
    if (target.containsKey(key2)) {
        int val1 = target.get(key2);
        target.put(key2, val1 + val2);
    } else {
        target.put(key2, val2);
...

Map<String, Object> result = new LinkedHashMap<String, Object>(original);
for (Map.Entry<String, Object> additionalEntry : additional.entrySet()) {
    String name = additionalEntry.getKey();
    Object additionalValue = additionalEntry.getValue();
    Object originalValue = original.get(name);
    Object newValue;
    if ((originalValue instanceof Map) && (additionalValue instanceof Map)) {
        Map<String, Object> innerAdditional = (Map<String, Object>) additionalValue;
...

Map<String, String> mergedPrefixes = new HashMap<String, String>();
mergedPrefixes.putAll(additionalPrefixes);
mergedPrefixes.putAll(prioritaryPrefixes); 
return mergedPrefixes;

ssio.forEach((k, v) -> {
    if (v != null) {
        Map<String, String> options = allOptions.get(k);
        if (options == null) {
            allOptions.put(k, v);
        } else {
            options.putAll(v);
});

Set<Entry<String, Set<T>>> subEntrySet = subPermMap.entrySet();
Iterator<Entry<String, Set<T>>> subEntryIterator = subEntrySet.iterator();
while (subEntryIterator.hasNext()) {
    Entry<String, Set<T>> subEntry = subEntryIterator.next();
    String permTypeName = subEntry.getKey();
    Set<T> permValueSet = subEntry.getValue();
    if (permMap.containsKey(permTypeName)) {
        permMap.get(permTypeName).addAll(permValueSet);
...

Map<K, V> resultMap = new HashMap<>();
for (K mapKey : map.keySet()) {
    resultMap.put(mapKey, map.get(mapKey));
for (Object propertyKey : properties.keySet()) {
    if ((overwrite) || (false == resultMap.containsKey((K) propertyKey))) {
        resultMap.put((K) propertyKey, (V) properties.get((K) propertyKey));
return resultMap;

final ResourceBundle bundle = ResourceBundle.getBundle(path);
final Enumeration<String> keyEnum = bundle.getKeys();
while (keyEnum.hasMoreElements()) {
    final String key = keyEnum.nextElement();
    final String assignment = bundle.getString(key);
    if (key.startsWith("+")) {
        final String baseKey = key.substring(1);
        final String initialAssignment = (String) map.get(baseKey);
...

if (template == null || "".equals(template) || segments == null) {
    throw new IllegalArgumentException(
            "Cannot operate on null template/segments, template must not be empty");
int vars = 0;
char[] chars = template.toCharArray();
for (int i = 0; i < chars.length; i++) {
    if (chars[i] == '{') {
...