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Java Collections

BBj runs on the JVM and gives you direct access to the entire Java Collections Framework. For key-value storage, use java.util.HashMap. For a Java-native dynamic list alternative to BBjVector, use java.util.ArrayList. The usage patterns are identical to Java itself -- use the class, instantiate it with new, and call methods normally.

java.util.HashMap​

HashMap is the standard choice for key-value storage in BBj. Create one, populate it with put(), and retrieve values with get():

use java.util.HashMap

map! = new HashMap()
map!.put("name", "Alice")
map!.put("role", "Developer")
map!.put("team", "Platform")

print "Name: ", map!.get("name")
print "Role: ", map!.get("role")

get() returns null() if the key does not exist. Use containsKey() to check before accessing, or handle the null return.

Iterating a HashMap​

HashMap does not guarantee iteration order. To walk all entries, use the keySet().iterator() pattern:

use java.util.HashMap
use java.util.Iterator

map! = new HashMap()
map!.put("name", "Alice")
map!.put("role", "Developer")
map!.put("team", "Platform")

rem Iterate using keySet().iterator()
iter! = map!.keySet().iterator()
while iter!.hasNext()
    key! = iter!.next()
    print key!, " = ", map!.get(key!)
wend

This is the standard Java iterator pattern. keySet() returns a Set of all keys, and iterator() gives you a one-pass traversal. Call hasNext() to check for remaining items, and next() to advance.

java.util.ArrayList​

ArrayList is Java's resizable list. It works similarly to BBjVector, and is useful when interacting with Java libraries that expect standard Java collection types:

use java.util.ArrayList

list! = new ArrayList()
list!.add("first")
list!.add("second")
list!.add("third")

for i = 0 to list!.size() - 1
    print list!.get(i)
next i

The API mirrors BBjVector: add() appends, get() retrieves by index, size() returns the count.

When to Use Which​

ScenarioUse
Dynamic list for BBjAPI methodsBBjVector
Dynamic list for Java library interopArrayList
Key-value pairs (any scenario)HashMap
Fixed-size typed dataDIM array

BBjVector is the default choice for lists in BBj code -- it integrates with BBjAPI methods that expect BBjVector parameters. Use ArrayList when you need to pass a list to a Java library that does not accept BBjVector, or when working in a purely Java-oriented context.

Why Not BBjHashMap?​

Older BBj code may use BBjHashMap for key-value storage. In BBj 20.10, BBjHashMap was renamed to BBjspHashMap and restricted to the BBJSP (server pages) subsystem. It is deprecated for general use.

Use java.util.HashMap instead. It provides the same functionality, is well-documented, and is the standard across the Java ecosystem.

For broader context on using Java classes from BBj, see the Java Interop chapter.

Reading Legacy Code

See Reading Legacy Code for BBjHashMap deprecation details and other historical collection patterns.

Further Reading