---
# DD Label: DD17
# Class: Example
# Method: demonstrateStringStripLeading
# FQN: io.github.biezhi.java11.string.Example
# File: src/main/java/io/github/biezhi/java11/string/Example.java
# Lines: 59-64 (6 LOC)
---

# (DD17) Business Logic — Example.demonstrateStringStripLeading() [6 LOC]

| Field | Value |
|-------|-------|
| Fully Qualified Name | `io.github.biezhi.java11.string.Example` |
| Layer | Utility (package `io.github.biezhi.java11.string` — JDK feature showcase) |
| Module | `string` (Package: `io.github.biezhi.java11.string`) |

## 1. Role

### Example.demonstrateStringStripLeading()

This method demonstrates the `String.stripLeading()` method introduced in JDK 11, which removes leading whitespace characters from a string. The method is a standalone utility/demo method belonging to a class that showcases various JDK 11 string features. It creates a sample string with both leading and trailing whitespace, prints a descriptive header identifying the operation being demonstrated, then prints the result of calling `stripLeading()` on that string — which removes only the leading whitespace while preserving any trailing whitespace. This method has no conditional branches and executes in a linear fashion, serving purely as an educational demonstration of a standard library feature. It is not called by any other method in the codebase, functioning as an entry point that would typically be invoked from a `main()` method or a demonstration runner. The method follows a consistent pattern shared across the class: declare a test string, emit a header via `writeHeader()`, then print the method result via `System.out.println()`.

## 2. Processing Pattern (Detailed Business Logic)

```mermaid
flowchart TD
    START(["demonstrateStringStripLeading()"])
    STEP1["Declare originalString with leading and trailing whitespace"]
    STEP2["CALL writeHeader with formatted header text"]
    STEP3["CALL System.out.println with stripLeading() result"]
    STEP4(["Return / Next"])

    START --> STEP1
    STEP1 --> STEP2
    STEP2 --> STEP3
    STEP3 --> STEP4
```

**Processing flow:**

1. **STEP1** — A string literal `"  biezhi.me  23333  "` with leading (2 spaces) and trailing (2 spaces) whitespace is assigned to the local variable `originalString`.
2. **STEP2** — The private static `writeHeader()` method is called with a formatted header string that identifies the operation: `"String.stripLeading() on '  biezhi.me  23333  '"`. This prints the header to `System.out`.
3. **STEP3** — `System.out.println` is called with the result of `originalString.stripLeading()`, which strips the leading whitespace and prints `"'biezhi.me  23333  '"` (leading spaces removed, trailing spaces preserved).

## 3. Parameter Analysis

| No | Parameter Name | Type | Business Description |
|----|---------------|------|---------------------|
| - | (none) | - | This method takes no parameters. It operates entirely on a locally-defined string literal. |

| No | Source | Field / State | Description |
|----|--------|--------------|-------------|
| 1 | Method | `originalString` | Local variable holding a sample string with leading and trailing whitespace for demonstration purposes. Value: `"  biezhi.me  23333  "`. |
| 2 | Class | `writeHeader()` | Private static method used to print a labeled header to `System.out` before each demonstration output. |

No instance fields or external state are read by this method.

## 4. CRUD Operations / Called Services

| CRUD | SC / CBS | SC Code | Entity / DB | Operation Description |
|------|----------|---------|-------------|----------------------|
| - | `Example.writeHeader` | - | - | Calls `writeHeader(String)` — a utility method that prints a header text to `System.out`. No data access. |
| - | `System.out.println` | - | - | Prints the result of `stripLeading()` to standard output. No data access. |

This method performs no CRUD operations. It is a pure demonstration utility with no database or persistence interactions.

## 5. Dependency Trace

| # | Caller (Screen/Batch) | Call Chain (Full Path to this Method) | Terminal (SC / CRUD / Entity) |
|---|----------------------|--------------------------------------|-------------------------------|
| - | (no callers found) | - | - |

No callers were found in the codebase. This method is a standalone demo entry point intended to be called directly from a main method or demonstration harness.

**Downstream calls from this method:**

| # | Called Method | Return Type | Purpose |
|---|--------------|-------------|---------|
| 1 | `writeHeader(String)` | `void` | Prints a formatted header identifying the operation being demonstrated |
| 2 | `System.out.println(Object)` | `void` | Outputs the stripped string result to standard output |

## 6. Per-Branch Detail Blocks

This method has no conditional branches, loops, or exception handling. It executes as a single linear block.

**Block 1** — [LINEAR EXECUTION] (L59–L64)

> Executes a sequence of declarations and calls to demonstrate `String.stripLeading()`.

| # | Type | Code |
|---|------|------|
| 1 | SET | `String originalString = "  biezhi.me  23333  ";` // Local variable with leading/trailing whitespace for demo |
| 2 | CALL | `writeHeader("String.stripLeading() on '" + originalString + "'");` // Prints header via writeHeader(String) |
| 3 | EXEC | `System.out.println("'" + originalString.stripLeading() + "'");` // Calls String.stripLeading(), prints result |
| 4 | RETURN | (implicit void return) |

**Behavior details:**

- **Line 60**: The string `"  biezhi.me  23333  "` contains 2 leading spaces, content, and 2 trailing spaces.
- **Line 62**: `writeHeader()` formats and prints: `String.stripLeading() on '  biezhi.me  23333  '`.
- **Line 63**: `originalString.stripLeading()` returns `"biezhi.me  23333  "` (leading whitespace removed, trailing whitespace preserved). Output: `'biezhi.me  23333  '`.

## 7. Glossary

| Term | Type | Business Meaning |
|------|------|------------------|
| `stripLeading()` | JDK 11 Method | A `String` instance method that removes all leading Unicode whitespace characters from a string. Returns a new string without modifying the original (strings are immutable in Java). |
| `stripTrailing()` | JDK 11 Method | A `String` instance method that removes all trailing Unicode whitespace characters. The complementary counterpart to `stripLeading()`. |
| `strip()` | JDK 11 Method | A `String` instance method that removes both leading and trailing whitespace. Combines the effects of `stripLeading()` and `stripTrailing()`. |
| whitespace | Technical term | Unicode whitespace characters as defined by `Character.isWhitespace()`, including spaces, tabs, newlines, and other format characters. |
| `writeHeader()` | Class Utility | A private static method in the `Example` class that prints a descriptive header string to `System.out` before demonstration output. |
| JDK 11 | Version | Java Development Kit version 11 (released September 2018), which introduced the `String.stripLeading()`, `String.stripTrailing()`, and `String.strip()` methods. |