Gets a system property string, or a replacement value if the property is
null or blank.

@param key
@param valueIfNull
@return
434050
public static String getString(String key, String valueIfNull) {
        String value = System.getProperty(key);
        if (Strings.isNullOrEmpty(value)) {
            return valueIfNull;
        }
        return value;
    }
95050
public static void setSystemPropertyIfIsNull(String key, Object value) {
        if (!System.getProperties().containsKey(key))
            System.setProperty(key, value.toString());
    }
1003823
public AnyValueMap getAsNullableMap(String key) {
		Object value = getAsObject(key);
		return value != null ? AnyValueMap.fromValue(value) : null;
	}
1207242
public int getIntProperty( String key , int defaultValue )
    {
        String value = SystemTools.replaceSystemProperties(settings.getProperty(key));
        if (value == null)
            return defaultValue;
        try
        {
            return Integer.parseInt(value);
        }
        catch (Exception e)
        {
            return defaultValue;
        }
    }
1247352
@SuppressWarnings("null")
	public static String value(String key, String defaultValue) {
		return System.getProperty(key, defaultValue);
	}
389142
@Override
    public String getString(@NonNull String key) {
        if (key == null) { throw new IllegalArgumentException("key cannot be null."); }

        final int index = indexForColumnName(key);
        return index >= 0 ? getString(index) : null;
    }
593175
@CheckResult @NonNull
  public Preference<String> getString(@NonNull String key, @NonNull String defaultValue) {
    checkNotNull(key, "key == null");
    checkNotNull(defaultValue, "defaultValue == null");
    return new RealPreference<>(preferences, key, defaultValue, StringAdapter.INSTANCE, keyChanges);
  }
887956
String getProperty(String key) {
        String value = properties.get(key);
        if (value == null) {
            throw new RuntimeException("No property value found for key " + key);
        }
        return value;
    }
1219775
public static synchronized String getProperty(String key, boolean required) {
		if (mProperties == null) {
			mProperties = initializeConfigurationProperties();
		}
		String value = mProperties.getProperty(key);
		if (value == null && required) {
			throw new RuntimeException("Property not found: " + key);
		}
		return value;
	}
838188
public Object getFirstValue(String key) {
    List values = fields.get(key);
    return values.size() > 0 ? values.get(0) : null;
  }
1072739
public boolean getBooleanProperty(String key) {
    requireNonNull(key);
    String value = properties.get(key);
    return value != null && Boolean.parseBoolean(value);
  }
1250436
private String getReqValue(Map<String, String[]> map, String key) {

        return map.get(key) != null ? map.get(key)[0] : null;
    }
836751
public @CheckForNull T get(String key) throws IOException {
        return get(key,false,null);
    }
1309485
public String getString(String key) {
	    Object obj = get(key);
	    if (obj != null && obj instanceof String) {
		    return (String) obj;
	        
		}
	    return null;
	    
	}
464460
public Optional<String> getString(String key) {
        Objects.requireNonNull(key, Required.KEY.toString());

        String value = this.values.get(key);
        if (StringUtils.isNotBlank(value)) {
            return Optional.of(value);
        }

        return Optional.empty();
    }
346046
public String getString(String key) throws MissingResourceException {
        // Error Checking Trace.  Ensure that we got a valid key
        if (key == null) {
            if (tc.isEventEnabled()) {

                // DGH20040823: Begin fix for defect 218797 - Source provided by Tom Musta
                // String msg = messages.getString("NLS.nullKey",
                //                                 "Null lookup key passed to NLS");
                String msg = getMessages().getString("NLS.nullKey",
                                                     "Null lookup key passed to NLS");
                // DGH20040823: End fix for defect 218797 - Source provided by Tom Musta
                Tr.warning(tc, msg);
            }
            return null;
        }
        // Error Checking Trace.  Ensure that we got a valid bundle.
        if (bundle == null) {
            if (tc.isEventEnabled()) {
                // DGH20040823: Begin fix for defect 218797 - Source provided by Tom Musta
                // String msg = messages.getString("NLS.noBundles",
                //                                 "Encountered an internal error. No valid bundles.");
                String msg = getMessages().getString("NLS.noBundles",
                                                     "Encountered an internal error. No valid bundles.");
                // DGH20040823: End fix for defect 218797 - Source provided by Tom Musta
                Tr.warning(tc, msg);
            }
            throw new MissingResourceException(bundleName, bundleName, key);
        }
        // Return Code.
        String rtn = null;
        // Get the resource (string).
        rtn = bundle.getString(key);
        return rtn;
    }
1297301
@Override
    public String getString(@NonNull String key) {
        if (key == null) { throw new IllegalArgumentException("key cannot be null."); }

        synchronized (lock) {
            final Object obj = getMValue(internalDict, key).asNative(internalDict);
            return obj instanceof String ? (String) obj : null;
        }
    }