THE Java™ Programming Language, Fourth Edition

public StringgetProperty(String key, String defaultElement)

Gets the property element for key. If the key is not found in this object, the

default Properties object (if any) is searched. Returns

defaultElement if the property is not found.

public ObjectsetProperty(String key, String value)

Adds the property key to the map with the given value. This only affects

the Properties object on which it is invokedthe default Properties

object (if any) is unaffected. Returns the previous value that was mapped to

this key, or null if there was none.

public voidstore(OutputStream out, String header)throws

IOException

Saves properties to an OutputStream. This only works if this

Properties object contains only string keys and values (as the

specification says it must); otherwise you get a ClassCastException. If

not null, the header string is written to the output stream as a single-line

comment. Do not use a multiline header string, or else the saved properties

will not be loadable. Only properties in this object are saved to the file; the

default Properties object (if any) is not saved.

public voidload(InputStream in)throws IOException

Loads properties from an InputStream. The property list is presumed to

have been created previously by store. This method puts values into this

Properties object; it does not set values in the default Properties

object.

public Enumeration<?>propertyNames()

Enumerates the keys, including those of any default Properties object.

This method provides a snapshot, and hence can be expensive. The inherited

keys method, by contrast, returns only those properties defined in this object

itself.

public voidlist(PrintWriter out)

Lists (prints) properties on the given PrintWriter. Useful for debugging.

public voidlist(PrintStream out)

Lists (prints) properties on the given PrintStream. Also useful for

debugging.

The default Properties object cannot be changed after the object is created. To change the default
Properties object, you can subclass the Properties class and modify the protected field named
defaults that contains the default Properties object.

Science is facts; just as houses are made of stones, so is science made of facts; but a pile of

stones is not a house and a collection of facts is not necessarily science.