SimpleBindings (Java Platform SE 8 )
Keywords: javax.script.SimpleBindings class
Date: 2026-04-17

compact1, compact2, compact3
javax.script

## Class SimpleBindings

- java.lang.Object
- - javax.script.SimpleBindings

- All Implemented Interfaces:
    Map<String,Object>, Bindings

      public class SimpleBindings
      extends Object
      implements Bindings

  A simple implementation of Bindings backed by a `HashMap` or some other specified `Map`.
  Since:
    1.6

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from interface java.util.Map

      `Map.Entry<K,V>`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `SimpleBindings()` Default constructor uses a `HashMap`.
    `SimpleBindings(Map<String,Object> m)` Constructor uses an existing `Map` to store the values.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `clear()` Removes all of the mappings from this map (optional operation).
    `boolean` | `containsKey(Object key)` Returns `true` if this map contains a mapping for the specified key.
    `boolean` | `containsValue(Object value)` Returns `true` if this map maps one or more keys to the specified value.
    `Set<Map.Entry<String,Object>>` | `entrySet()` Returns a `Set` view of the mappings contained in this map.
    `Object` | `get(Object key)` Returns the value to which this map maps the specified key.
    `boolean` | `isEmpty()` Returns `true` if this map contains no key-value mappings.
    `Set<String>` | `keySet()` Returns a `Set` view of the keys contained in this map.
    `Object` | `put(String name, Object value)` Sets the specified key/value in the underlying `map` field.
    `void` | `putAll(Map<? extends String,? extends Object> toMerge)` `putAll` is implemented using `Map.putAll`.
    `Object` | `remove(Object key)` Removes the mapping for this key from this map if it is present (optional operation).
    `int` | `size()` Returns the number of key-value mappings in this map.
    `Collection<Object>` | `values()` Returns a `Collection` view of the values contained in this map.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

    - ### Methods inherited from interface java.util.Map

      `compute, computeIfAbsent, computeIfPresent, equals, forEach, getOrDefault, hashCode, merge, putIfAbsent, remove, replace, replace, replaceAll`

- - ### Constructor Detail

    - #### SimpleBindings

          public SimpleBindings(Map<String,Object> m)

      Constructor uses an existing `Map` to store the values.
      Parameters:
        `m` - The `Map` backing this `SimpleBindings`.
      Throws:
        `NullPointerException` - if m is null

    - #### SimpleBindings

          public SimpleBindings()

      Default constructor uses a `HashMap`.

  - ### Method Detail

    - #### put

          public Object put(String name,
                            Object value)

      Sets the specified key/value in the underlying `map` field.
      Specified by:
        `put` in interface `Map<String,Object>`
      Specified by:
        `put` in interface `Bindings`
      Parameters:
        `name` - Name of value
        `value` - Value to set.
      Returns:
        Previous value for the specified key. Returns null if key was previously unset.
      Throws:
        `NullPointerException` - if the name is null.
        `IllegalArgumentException` - if the name is empty.

    - #### putAll

          public void putAll(Map<? extends String,? extends Object> toMerge)

      `putAll` is implemented using `Map.putAll`.
      Specified by:
        `putAll` in interface `Map<String,Object>`
      Specified by:
        `putAll` in interface `Bindings`
      Parameters:
        `toMerge` - The `Map` of values to add.
      Throws:
        `NullPointerException` - if toMerge map is null or if some key in the map is null.
        `IllegalArgumentException` - if some key in the map is an empty String.

    - #### clear

          public void clear()

      Removes all of the mappings from this map (optional operation). The map will be empty after this call returns.
      Specified by:
        `clear` in interface `Map<String,Object>`

    - #### containsKey

          public boolean containsKey(Object key)

      Returns `true` if this map contains a mapping for the specified key. More formally, returns `true` if and only if this map contains a mapping for a key `k` such that `(key==null ? k==null : key.equals(k))`. (There can be at most one such mapping.)
      Specified by:
        `containsKey` in interface `Map<String,Object>`
      Specified by:
        `containsKey` in interface `Bindings`
      Parameters:
        `key` - key whose presence in this map is to be tested.
      Returns:
        `true` if this map contains a mapping for the specified key.
      Throws:
        `NullPointerException` - if key is null
        `ClassCastException` - if key is not String
        `IllegalArgumentException` - if key is empty String

    - #### containsValue

          public boolean containsValue(Object value)

      Returns `true` if this map maps one or more keys to the specified value. More formally, returns `true` if and only if this map contains at least one mapping to a value `v` such that `(value==null ? v==null : value.equals(v))`. This operation will probably require time linear in the map size for most implementations of the `Map` interface.
      Specified by:
        `containsValue` in interface `Map<String,Object>`
      Parameters:
        `value` - value whose presence in this map is to be tested
      Returns:
        `true` if this map maps one or more keys to the specified value

    - #### entrySet

          public Set<Map.Entry<String,Object>> entrySet()

      Returns a `Set` view of the mappings contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own `remove` operation, or through the `setValue` operation on a map entry returned by the iterator) the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the `Iterator.remove`, `Set.remove`, `removeAll`, `retainAll` and `clear` operations. It does not support the `add` or `addAll` operations.
      Specified by:
        `entrySet` in interface `Map<String,Object>`
      Returns:
        a set view of the mappings contained in this map

    - #### get

          public Object get(Object key)

      Returns the value to which this map maps the specified key. Returns `null` if the map contains no mapping for this key. A return value of `null` does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to `null`. The `containsKey` operation may be used to distinguish these two cases.

      More formally, if this map contains a mapping from a key `k` to a value `v` such that `(key==null ? k==null : key.equals(k))`, then this method returns `v`; otherwise it returns `null`. (There can be at most one such mapping.)

      Specified by:
        `get` in interface `Map<String,Object>`
      Specified by:
        `get` in interface `Bindings`
      Parameters:
        `key` - key whose associated value is to be returned.
      Returns:
        the value to which this map maps the specified key, or `null` if the map contains no mapping for this key.
      Throws:
        `NullPointerException` - if key is null
        `ClassCastException` - if key is not String
        `IllegalArgumentException` - if key is empty String

    - #### isEmpty

          public boolean isEmpty()

      Returns `true` if this map contains no key-value mappings.
      Specified by:
        `isEmpty` in interface `Map<String,Object>`
      Returns:
        `true` if this map contains no key-value mappings

    - #### keySet

          public Set<String> keySet()

      Returns a `Set` view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own `remove` operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the `Iterator.remove`, `Set.remove`, `removeAll`, `retainAll`, and `clear` operations. It does not support the `add` or `addAll` operations.
      Specified by:
        `keySet` in interface `Map<String,Object>`
      Returns:
        a set view of the keys contained in this map

    - #### remove

          public Object remove(Object key)

      Removes the mapping for this key from this map if it is present (optional operation). More formally, if this map contains a mapping from key `k` to value `v` such that `(key==null ? k==null : key.equals(k))`, that mapping is removed. (The map can contain at most one such mapping.)

      Returns the value to which the map previously associated the key, or `null` if the map contained no mapping for this key. (A `null` return can also indicate that the map previously associated `null` with the specified key if the implementation supports `null` values.) The map will not contain a mapping for the specified key once the call returns.

      Specified by:
        `remove` in interface `Map<String,Object>`
      Specified by:
        `remove` in interface `Bindings`
      Parameters:
        `key` - key whose mapping is to be removed from the map.
      Returns:
        previous value associated with specified key, or `null` if there was no mapping for key.
      Throws:
        `NullPointerException` - if key is null
        `ClassCastException` - if key is not String
        `IllegalArgumentException` - if key is empty String

    - #### size

          public int size()

      Returns the number of key-value mappings in this map. If the map contains more than `Integer.MAX_VALUE` elements, returns `Integer.MAX_VALUE`.
      Specified by:
        `size` in interface `Map<String,Object>`
      Returns:
        the number of key-value mappings in this map

    - #### values

          public Collection<Object> values()

      Returns a `Collection` view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress (except through the iterator's own `remove` operation), the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the `Iterator.remove`, `Collection.remove`, `removeAll`, `retainAll` and `clear` operations. It does not support the `add` or `addAll` operations.
      Specified by:
        `values` in interface `Map<String,Object>`
      Returns:
        a collection view of the values contained in this map

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