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Practical Java Libraries

BBj 25.x bundles several useful Java libraries beyond the standard JDK. This section shows practical, copy-paste examples for the libraries you will reach for most often: JSON parsing, HTTP requests, encoding, hashing, and unique ID generation.

JSON with org.json (Bundled)​

The org.json library (json-20250107.jar) ships with BBj 25.x -- no external JAR needed and no classpath configuration required.

Creating JSON:

use org.json.JSONObject
use org.json.JSONArray

rem Create a JSON object
json! = new JSONObject()
json!.put("name", "Alice")
json!.put("role", "Developer")
json!.put("active", BBjAPI.TRUE)

rem Add a nested array
skills! = new JSONArray()
skills!.put("BBj")
skills!.put("Java")
skills!.put("SQL")
json!.put("skills", skills!)

rem Pretty-print with 2-space indent
print json!.toString(2)

Parsing JSON:

use org.json.JSONObject
use org.json.JSONArray

rem Parse a JSON string
parsed! = new JSONObject("{""name"":""Bob"",""age"":30,""active"":true}")
print "Name: ", parsed!.getString("name")
print "Age: ", str(parsed!.getInt("age"))

rem Check if a key exists before accessing
if parsed!.has("email") then
    print "Email: ", parsed!.getString("email")
else
    print "No email on record"
fi

rem Parse a JSON array
arr! = new JSONArray("[""red"",""green"",""blue""]")
for i = 0 to arr!.length() - 1
    print arr!.getString(i)
next i

HTTP Requests with HttpURLConnection​

java.net.HttpURLConnection is available in the standard JDK and works for both GET and POST requests.

GET request:

use java.net.URL
use java.net.HttpURLConnection
use java.io.BufferedReader
use java.io.InputStreamReader

rem Simple GET request
url! = new URL("https://httpbin.org/get")
conn! = cast(HttpURLConnection, url!.openConnection())
conn!.setRequestMethod("GET")

code = conn!.getResponseCode()
print "Response code: ", code

rem Read response body
reader! = new BufferedReader(new InputStreamReader(conn!.getInputStream()))
line! = reader!.readLine()
while line! <> null()
    print line!
    line! = reader!.readLine()
wend
reader!.close()
conn!.disconnect()

POST request:

use java.net.URL
use java.net.HttpURLConnection
use java.io.BufferedReader
use java.io.InputStreamReader
use java.io.OutputStreamWriter

url! = new URL("https://httpbin.org/post")
conn! = cast(HttpURLConnection, url!.openConnection())
conn!.setRequestMethod("POST")
conn!.setRequestProperty("Content-Type", "application/json")
conn!.setDoOutput(BBjAPI.TRUE)

rem Write request body
writer! = new OutputStreamWriter(conn!.getOutputStream())
writer!.write("{""message"":""Hello from BBj""}")
writer!.flush()
writer!.close()

print "Response code: ", conn!.getResponseCode()

rem Read response
reader! = new BufferedReader(new InputStreamReader(conn!.getInputStream()))
line! = reader!.readLine()
while line! <> null()
    print line!
    line! = reader!.readLine()
wend
reader!.close()
conn!.disconnect()

java.net.http.HttpClient (Java 11+) is also available as a more modern alternative, but HttpURLConnection is simpler for basic requests and more commonly seen in existing BBj code.

Base64 Encoding and Decoding​

java.util.Base64 provides standard Base64 encoding and decoding. A common use is encoding credentials for API authentication headers.

use java.util.Base64

rem Encode a string to Base64
encoder! = Base64.getEncoder()
encoded$ = encoder!.encodeToString(new java.lang.String("Hello BBj").getBytes())
print "Encoded: ", encoded$

rem Decode back to original
decoder! = Base64.getDecoder()
decoded! = new java.lang.String(decoder!.decode(encoded$))
print "Decoded: ", decoded!

rem Practical: encode API credentials
credentials$ = "api_user:api_secret"
auth$ = encoder!.encodeToString(new java.lang.String(credentials$).getBytes())
print "Authorization: Basic ", auth$

Hashing with MessageDigest​

java.security.MessageDigest supports SHA-256, SHA-512, MD5, and other hash algorithms. SHA-256 is recommended for general use.

use java.security.MessageDigest

rem SHA-256 hash
md! = MessageDigest.getInstance("SHA-256")
hash! = md!.digest(new java.lang.String("password123").getBytes())

rem Convert bytes to hex string
sb! = new StringBuilder()
for i = 0 to hash!.length - 1
    sb!.append(String.format("%02x", hash![i]))
next i
print "SHA-256: ", sb!.toString()

MD5 is also available (MessageDigest.getInstance("MD5")) but SHA-256 is preferred. Note that for actual password storage, use a dedicated password hashing library (bcrypt, scrypt) rather than raw SHA-256 -- raw hashes are fast to brute-force.

UUID Generation​

java.util.UUID generates RFC 4122 compliant unique identifiers in a single line:

use java.util.UUID

uuid! = UUID.randomUUID()
print "UUID: ", uuid!.toString()

UUIDs are useful for generating unique record identifiers, session tokens, or correlation IDs for logging.

What Else is Available​

With Java 21, you have access to the entire JDK standard library. BBj 25.x also bundles several third-party JARs including Google Gson (gson-2.12.1.jar) and json-smart (json-smart-2.5.2.jar). For a full list of bundled libraries, see the BBj 25.x Classpath Overview.

If you need a library beyond what is bundled, add its JAR to the classpath via Enterprise Manager (see the Advanced Patterns page for details).

Reading Legacy Code

See Reading Legacy Code for legacy Java interop patterns including string-based data exchange and procedural Java usage.

Further Reading