You want to create two beans of the same type but only one should be active based on a property mode which can be "simple" or "advanced".
hard📝 Application Q15 of 15
Spring Boot - Advanced Patterns
You want to create two beans of the same type but only one should be active based on a property mode which can be "simple" or "advanced". Which is the best way to define these beans using @ConditionalOnProperty?
AUse <code>@ConditionalOnProperty(name = "mode", havingValue = "simple")</code> on the simple bean and <code>@ConditionalOnProperty(name = "mode", havingValue = "advanced")</code> on the advanced bean
BUse <code>@ConditionalOnProperty(name = "mode")</code> on both beans without havingValue
CCreate both beans without conditions and select one at runtime
DUse <code>@ConditionalOnProperty(name = "mode", matchIfMissing = true)</code> on both beans
Step-by-Step Solution
Solution:
Step 1: Understand the requirement
Only one bean should be active depending on the property value "simple" or "advanced".
Step 2: Apply conditional annotations
Using @ConditionalOnProperty with havingValue set to "simple" or "advanced" on each bean ensures only one bean loads.
Step 3: Evaluate other options
Use @ConditionalOnProperty(name = "mode") on both beans without havingValue lacks value check, so both beans may load; Create both beans without conditions and select one at runtime loads both always; Use @ConditionalOnProperty(name = "mode", matchIfMissing = true) on both beans activates both if property missing.
Final Answer:
Use @ConditionalOnProperty(name = "mode", havingValue = "simple") on the simple bean and @ConditionalOnProperty(name = "mode", havingValue = "advanced") on the advanced bean -> Option A
Quick Check:
Use havingValue to select one bean by property [OK]
Quick Trick:Use havingValue to pick one bean per property value [OK]
Common Mistakes:
Not specifying havingValue causing both beans to load
Trying to select bean at runtime instead of conditionally
Using matchIfMissing on both beans causing conflicts
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