1# Java Spring Boot Patterns
2 
3## Design Patterns
4 
5### Pattern 1: Input Validation
6 
7Always validate input before processing:
8 
9```python
10def validate_input(data):
11    if data is None:
12        raise ValueError("Data cannot be None")
13    if not isinstance(data, dict):
14        raise TypeError("Data must be a dictionary")
15    return True
16```
17 
18### Pattern 2: Error Handling
19 
20Use consistent error handling:
21 
22```python
23try:
24    result = risky_operation()
25except SpecificError as e:
26    logger.error(f"Operation failed: {e}")
27    handle_error(e)
28except Exception as e:
29    logger.exception("Unexpected error")
30    raise
31```
32 
33### Pattern 3: Configuration Loading
34 
35Load and validate configuration:
36 
37```python
38import yaml
39 
40def load_config(config_path):
41    with open(config_path) as f:
42        config = yaml.safe_load(f)
43    validate_config(config)
44    return config
45```
46 
47## Anti-Patterns to Avoid
48 
49### ❌ Don't: Swallow Exceptions
50 
51```python
52# BAD
53try:
54    do_something()
55except:
56    pass
57```
58 
59### ✅ Do: Handle Explicitly
60 
61```python
62# GOOD
63try:
64    do_something()
65except SpecificError as e:
66    logger.warning(f"Expected error: {e}")
67    return default_value
68```
69 
70## Category-Specific Patterns: General
71 
72### Recommended Approach
73 
741. Start with the simplest implementation
752. Add complexity only when needed
763. Test each addition
774. Document decisions
78 
79### Common Integration Points
80 
81- Configuration: `assets/config.yaml`
82- Validation: `scripts/validate.py`
83- Documentation: `references/GUIDE.md`
84 
85---
86 
87*Pattern library for java-spring-boot skill*
88