at org.apache.commons.lang3.ClassUtils.isAssignable(ClassUtils.java:760) ~[commons-lang3-3.7.jar:3.7] 查看源码是: 也就是JAVA_SPECIFICATION_VERSION_AS_ENUM 为null, 它来源是: public static final String JAVA_SPECIFICATION_VERSION = getSystemProperty("java.specification.version"); private static fina...
也就是JAVA_SPECIFICATION_VERSION_AS_ENUM 为null, 它来源是: public static final String JAVA_SPECIFICATION_VERSION = getSystemProperty("java.specification.version"); private static final JavaVersion JAVA_SPECIFICATION_VERSION_AS_ENUM = JavaVersion.get(JAVA_SPECIFICATION_VERSION); 感觉跟jdk 版本有关, ...
EN上述代码在进行查询的时候如果没有查询到任何值，那么selectOne会返回null，并把null赋值给user对象。这...
/** *以 findOne 为例 */ public T findOne(Specification<T> spec) { try { return getQuery(spec, (Sort) null).getSingleResult(); } catch (NoResultException e) { return null; } } /* * 解析 Specification,利用 EntityManager 直接实现调用逻辑。 */ protected <S extends T> TypedQuery<S> g...
Note that when using an enumeration type as the type of a set or as the type of the keys in a map, specialized and efficient set and map implementations are available. See Java Language Specification: 8.9 Enum Classes8.9.3 Enum Members Since: 1.5 See Also: Class.getEnumConstants() EnumSet...
According to the Java language specification, these are minimal ranges. So the behaviour is implementation dependent. Object intering saves time and space. Objects obtained from literals, autoboxing andInteger.valueOfare interned objects while those constructed with new operator are always distinct object...
For more information, see the definition ofbinary namein theJava Language Specification, Second Edition. Serialization- Changes in compiler-generated synthetics affect the default serial version UID, and therefore can cause serialization incompatibility when that UID is not explicitly overridden. ...
3. If the object is null, null is put in the stream and writeObject returns.4. If the object has been previously replaced, as described in Step 8, write the handle of the replacement to the stream and writeObject returns.5. If the object has already been written to the stream, its ...
The types accepted by an annotation are strictly limited; they can only be primitives, String, Class, enum types, annotation types, and arrays of the preceding types. Passes parameters must always be non-null compile-time constants. Understanding what effect the annotations shown in this example ...
from the stream <LI> The class contains unknown datatypes <LI> The class does not have an accessible no-arg constructor <LI> The ObjectStreamClass of an enum constant does not represent an enum type <LI> Other conditions given in the Java Object Serialization Specification </U...