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  1. ,
    Expert tip

    Try indicating constructor to use @JsonCreator annotation.

  2. ,

    The easiest solution is to provide a default constructor for the class you want to convert from/to json.

Solutions on the web

via archlinux.org by Unknown author, 1 year ago
Can not find a (Map) Key deserializer for type [simple type, class cc.arduino.contributions.packages.ContributedToolReference]
via Stack Overflow by Comencau
, 2 years ago
Can not find a (Map) Key deserializer for type [collection type; class java.util.ArrayList, contains [simple type, class java.lang.Long]]
via GitHub by fdinoff
, 2 years ago
Can not find a (Map) Key deserializer for type [array type, component type: [simple type, class byte]]
via Stack Overflow by Gili
, 1 year ago
Can not find a (Map) Key deserializer for type [simple type, class java.lang.Class<java.lang.Object>]
via Stack Overflow by Shoner Sul
, 1 year ago
via spring.io by Unknown author, 1 year ago
com.fasterxml.jackson.databind.JsonMappingException: Can not find a (Map) Key deserializer for type [simple type, class cc.arduino.contributions.packages.ContributedToolReference]	at com.fasterxml.jackson.databind.deser.DeserializerCache._handleUnknownKeyDeserializer(DeserializerCache.java:584)	at com.fasterxml.jackson.databind.deser.DeserializerCache.findKeyDeserializer(DeserializerCache.java:171)	at com.fasterxml.jackson.databind.DeserializationContext.findKeyDeserializer(DeserializationContext.java:347)	at com.fasterxml.jackson.databind.deser.std.MapDeserializer.createContextual(MapDeserializer.java:232)	at com.fasterxml.jackson.databind.DeserializationContext.findContextualValueDeserializer(DeserializationContext.java:309)	at com.fasterxml.jackson.databind.deser.std.StdDeserializer.findDeserializer(StdDeserializer.java:634)	at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.resolve(BeanDeserializerBase.java:438)	at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:298)	at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCacheValueDeserializer(DeserializerCache.java:247)	at com.fasterxml.jackson.databind.deser.DeserializerCache.findValueDeserializer(DeserializerCache.java:146)	at com.fasterxml.jackson.databind.DeserializationContext.findContextualValueDeserializer(DeserializationContext.java:305)	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.createContextual(CollectionDeserializer.java:151)	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.createContextual(CollectionDeserializer.java:23)	at com.fasterxml.jackson.databind.DeserializationContext.findContextualValueDeserializer(DeserializationContext.java:309)	at com.fasterxml.jackson.databind.deser.std.StdDeserializer.findDeserializer(StdDeserializer.java:634)	at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.resolve(BeanDeserializerBase.java:438)	at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:298)	at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCacheValueDeserializer(DeserializerCache.java:247)	at com.fasterxml.jackson.databind.deser.DeserializerCache.findValueDeserializer(DeserializerCache.java:146)	at com.fasterxml.jackson.databind.DeserializationContext.findRootValueDeserializer(DeserializationContext.java:322)	at com.fasterxml.jackson.databind.ObjectMapper._findRootDeserializer(ObjectMapper.java:2990)	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2884)	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2080)	at cc.arduino.contributions.packages.ContributionsIndexer.parseIndex(ContributionsIndexer.java:180)	at cc.arduino.contributions.packages.ContributionsIndexer.parseIndex(ContributionsIndexer.java:86)	at processing.app.BaseNoGui.initPackages(BaseNoGui.java:599)	at processing.app.Base.(Base.java:295)	at processing.app.Base.guardedMain(Base.java:222)	at processing.app.Base.main(Base.java:135)