Java SE 17 (1Z0-829) case studies
Java SE 17 (1Z0-829) · Put your knowledge to work in context.
The Java SE 17 Developer credential, tracked as exam 1Z0-829, is the Oracle certification exam for programmers who work with modern Java on the Java SE 17 platform. It suits developers who already write Java daily and want a formal credential that demonstrates command of the language as it stands at the 17 release, rather than an entry-level certificate for newcomers. The Java SE 17 (1Z0-829) case studies are 5 cases and about 3,832 words.
1Leap-Day Invoice Run Fails on a Strict Parse
A billing service generates monthly invoices. The renewal date is read from a config file, parsed with DateTimeFormatter.ofPattern("yyyy-MM-dd").withResolverStyle(ResolverStyle.STRICT) and LocalDate.parse.
681 words, about 3 min2Order Totals: Duplicate Keys, Ordering and a Silent Race
An order-analytics job consumes a List<Order ; Order is a record with customerId, region and a BigDecimal amount. Version 1 collects totals with orders.stream().collect(Collectors.toMap(Order::customerId, Order::amount)).
738 words, about 4 min3Payroll Bands: Fall-Through, a Missing yield and an Unboxing NPE
A payroll utility assigns tax bands. Version A uses a classic switch statement over an int bonus: case 0 assigns band 1 with no break, case 1 assigns band 2 and breaks, default assigns band 3.
849 words, about 4 min4Import Service: Suppressed Exceptions, Catch Order and var Boundaries
A nightly import service opens two resources in one try-with-resources header: try (BufferedReader in = new BufferedReader(new FileReader(path)); AuditLog log = new AuditLog(logDir)) { process(in); }. AuditLog implements AutoCloseable; its close() flushes to disk and can throw IOException.
785 words, about 4 min5Pricing Engine: Default Conflicts, Function Order and a Mutable Record Key
A pricing engine defines interface Discount { BigDecimal apply(BigDecimal p); default String label() { return labelWith("discount"); } private String labelWith(String s) { return "[" + s + "]"; } } and interface Loyalty { default String label() { return "loyalty"; } }. class Combo implements Discount, Loyalty { public BigDecimal apply(BigDecimal p) { return p; } } is rejected by javac.
779 words, about 4 min