Null-safe String intern method.
@return A canonical representation for the string object. Null for null input strings
431607
@Nullable
    public static String intern(@CheckForNull String s) {
        return s==null ? s : s.intern();
    }
692670
@CheckReturnValue
  public Joiner useForNull(final String nullText) {
    checkNotNull(nullText);
    return new Joiner(this) {
      @Override CharSequence toString(@Nullable Object part) {
        return (part == null) ? nullText : Joiner.this.toString(part);
      }

      @Override public Joiner useForNull(String nullText) {
        throw new UnsupportedOperationException("already specified useForNull");
      }

      @Override public Joiner skipNulls() {
        throw new UnsupportedOperationException("already specified useForNull");
      }
    };
  }
565317
public java.util.List<String> getStringSetValue() {
        if (stringSetValue == null) {
            stringSetValue = new com.amazonaws.internal.SdkInternalList<String>();
        }
        return stringSetValue;
    }
265437
private String ifNull(){

        if(params.length != 2){
            throw new IllegalArgumentException("Wrong number of Parameters for if null expression");
        }

        final String field1 = record.getValueByFieldName(params[0]);
        if (!field1.isEmpty()){
            return field1;
        }
        final String field2 = record.getValueByFieldName(params[1]);
        return field2;
    }
1351968
public static String urlEncode(String str) throws UnsupportedEncodingException {
    // Preserve original behavior that passing null for an object id will lead
    // to us actually making a request to /v1/foo/null
    if (str == null) {
      return null;
    } else {
      // Don't use strict form encoding by changing the square bracket control
      // characters back to their literals. This is fine by the server, and
      // makes these parameter strings easier to read.
      return URLEncoder.encode(str, CHARSET)
        .replaceAll("%5B", "[")
        .replaceAll("%5D", "]");
    }
  }
1296851
public String throwableToString() {
        StringBuilder sb = new StringBuilder("Exception:  ");
        if (throwable != null)
            sb.append(throwable.toString());
        else
            sb.append("null");
        sb.append("\n");
        return sb.toString();
    }
456408
public String getNextString()
    {
        Object data = this.getNextData();
        if (data instanceof String)
            return (String)data;
        return null;    // EOF
    }
521104
@Nullable
  public String singleVar() {
    if (bindings.size() == 1) {
      return bindings.entrySet().iterator().next().getKey();
    }
    return null;
  }
711440
public String getAsString()
   {

      if (stringName == null)
      {

         StringBuilder str = new StringBuilder();
         for (int i = 0; i < getLength(); i++)
         {
            str.append(names[i].getAsString(true));
         }
         stringName = str.toString();
      }

      return stringName;
   }
151209
private static <T> StringConverter<T> defaultStringConverter() {
        return new StringConverter<T>() {
            @Override
            public String toString(T t) {
                return t == null ? null : t.toString();
            }

            @Override
            public T fromString(String string) {
                return (T) string;
            }
        };
    }
536617
@Nullable
    public final Charset getEncoding() {
        final String parameter = getParameter(ENCODING);
        if (parameter == null) {
            return null;
        }
        return Charset.forName(parameter);
    }
191971
@SuppressWarnings("unused")
    public static List<String> internListOf(Object... objects) {
        if (objects == null || objects.length == 0) {
            return Collections.emptyList();
        }
        List<String> strings = new ArrayList<>(objects.length);
        for (Object object : objects) {
            strings.add(object.toString().intern());
        }
        return Collections.unmodifiableList(strings);
    }
1067122
public Object intern(Object keyArg) {
        boolean nullKey = false;
        if (keyArg == null) {
            nullKey = true;
            keyArg = UniqueTag.NULL_VALUE;
        }
        int index = ensureIndex(keyArg);
        values[index] = 0;
        return (nullKey) ? null : keys[index];
    }
919327
public JsonWriter nullValue() throws IOException {
    if (deferredName != null) {
      if (serializeNulls) {
        writeDeferredName();
      } else {
        deferredName = null;
        return this; // skip the name and the value
      }
    }
    beforeValue();
    out.write("null");
    return this;
  }
200589
public static StringUtil getInstance() {

    if (instance == null) {
      synchronized (StringUtilImpl.class) {
        if (instance == null) {
          instance = new StringUtilImpl();
        }
      }
    }
    return instance;
  }
613695
public static String initCap(String str) {
        assertStringNotNull(str);
        if (is_Null_or_Empty(str)) {
            return str;
        }
        if (str.length() == 1) {
            return str.toUpperCase();
        }
        final char chars[] = str.toCharArray();
        chars[0] = Character.toUpperCase(chars[0]);
        return new String(chars);
    }
1052688
public synchronized E intern(@NonNull final E object) {
      return map.computeIfAbsent(object, o -> object);
   }