Differences

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--- swdev:java:lang:arraylist [2017/10/25 08:34]
smayr [List]
+++ swdev:java:lang:arraylist [2017/10/25 08:49] (current)
smayr [ArrayList]
@@ Line 1: / Line 1: @@
+= List =
+List is a generic class that can handle most data.
+Initializing a ''List'':
+<code java>
+import java.util.ArrayList;
+import java.util.List;
+// Method 1
+List<Object> arr = Arrays.asList(
+, "10001", "Acme Inc.", 1, null
+);
+// Method 2
+List<Object> arr = new ArrayList<Object>();
+arr.add(1);
+arr.add("10001");
+arr.add("Acme Inc.");
+arr.add(1);
+arr.add(null);
+</code>
 = ArrayList =
 ''ArrayList'' is derived from ''List''. It can handle mixed primitives (as ''Object'').
@@ Line 31: / Line 53: @@
 </code>
+To process each object with the correct type:
+<code java>
+ArrayList<Object> listOfObjects = new ArrayList<Object>();
+for(Object obj: listOfObjects) {
+   if (obj instanceof String) {
+       // handle String
+   } else if (obj instanceof Integer) {
+       // handle Integer
+   } else {
+       // handle others
+   }
+}
+</code>